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Nitrogen resorption machanism during leaf senescence in woody plants YANG Jiading, LIU Yujie, FENG Jianyuan, ZHANG Yuanlan JOURNAL OF NANJING FORESTRY UNIVERSITY    2023, 47 (5): 1-8.   DOI: 10.12302/j.issn.1000-2006.202212004 Abstract （1151）   HTML （52）    PDF（pc） （1492KB）（16763）       Knowledge map    Save The application of nitrogen fertilizer is the main driving force for biomass production in artificial systems of agriculture and forestry. However, problems such as the increased cost and substantial pollution of soil, water and atmosphere are resulted from nitrogen leaching. Improving plant nitrogen use efficiency (NUE) is the crucial way to resolve these problems. NUE is a complex trait associated with an interplay between the genetic background and environmental factors, and is the comprehensive reflection of respective efficiencies with uptake of soil nitrogen by plant roots, assimilation and utilization of absorbed nitrogen inside plants, and resorption of nitrogen from senescent tissues or organs. The physiological steps of nitrogen resorption include a protein degradation in senescing organs,amino acid interconversion, and phloem loading of amino acids for remobilization. Phloem loading is thought to be the rate-limiting step of nitrogen resorption from senescing leaves. Nitrogen resorption is always accompanied with either natural senescence of the whole plant or certain tissues/organs determined by a developmental age or precocious senescence induced by environmental stresses. Nitrogen resorption in senescing leaves is an important strategy for perennial woody plants to conserve intrinsic nitrogen and increase stress tolerance through the winter season. The efficiency of nitrogen resorption is not only associated with species, age and functional types (i.e. deciduous or evergreen, broad- or needle-leaved) of woody plants, but also influenced by environmental factors such as geographic habitat, status of soil nitrogen and water supply. Improving efficiency of nitrogen resorption from senescing leaves may alleviate the requirement of trees for nitrogen fertilizer in the next growth season. As studies about mechanisms of leaf senescence and nitrogen resorption in trees are rare at present, characterization of key factors (such as NAC and WRKY family members) regulating leaf senescence, certain transporters responsible for phloem loading of amino acids in senescing leaves and signaling components mediating functions of phytohormones (such as abscisic acid and ethylene) which may promote leaf senescence is desired in woody plants in coming years, thus providing putative technological supports for breeding tree cultivars with the improved NUE through the genetic modification. Reference | Related Articles | Metrics | Comments（0） Cited:

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Taxonomic and geographic differentiation of phylogenetic conservatism of plant functional traits: a case study of maximum plant height of Chinese angiosperms XING Bingbing, LI Yao, MAO Lingfeng JOURNAL OF NANJING FORESTRY UNIVERSITY    2024, 48 (1): 59-66.   DOI: 10.12302/j.issn.1000-2006.202204044 Abstract （2776）   HTML （39）    PDF（pc） （3438KB）（8219）       Knowledge map    Save 【Objective】 Plant height is a fundamental component of plant ecological strategies. This study aims to elucidate the phylogenetic conservatism of maximum plant height in Chinese angiosperms, investigate its variation across taxonomic groups and geographic regions, and explore its associations with environmental factors. 【Method】 Using data on the maximum plant height and geographic distribution of 20 295 Chinese angiosperm species, this study assessed the phylogenetic conservatism of maximum plant height among different growth forms, taxonomic groups, and vegetation zones. The study analyzed the correlation between the phylogenetic signal (Pagel’s λ) and factors such as latitude, temperature, and precipitation. 【Result】 The maximum plant height of Chinese angiosperms exhibited a strong phylogenetic conservatism (Pagel’s λ = 0.893). Among them, herbaceous plants showed slightly lower phylogenetic conservatism compared to woody plants, while six orders including Fabales exhibited phylogenetic signals higher than 0.9. The phylogenetic signals of all plants and woody plants displayed a unimodal relationship with latitude and temperature but showed a negative correlation with precipitation. The latitudinal pattern of phylogenetic signals in herbaceous plants was less pronounced, instead showing a multi-peak relationship with temperature and precipitation. 【Conclusion】 The maximum plant height of Chinese angiosperms demonstrated a clear geographic pattern in terms of phylogenetic conservatism, but the trend varied among different growth forms. Overall, the phylogenetic conservatism of maximum plant height of angiosperms and woody plants was stronger in middle latitudes compared to both high and low latitudes. Table and Figures | Reference | Related Articles | Metrics | Comments（0）

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Professor Cheng Wan-chun and Dendrology FANG Yanming JOURNAL OF NANJING FORESTRY UNIVERSITY    2024, 48 (3): 2-13.   DOI: 10.12302/j.issn.1000-2006.202404034 Abstract （3389）   HTML （316）    PDF（pc） （3315KB）（5166）       Knowledge map    Save As a distinguished dendrologist, forester, and forestry educator, Professor Cheng Wan-chun (1904-1983) devoted his life to the pursuit of dendrology science and education. As a learner of dendrology, he was diligent and eager to learn, lucky to meet good tutors, and had a well-rounded approach to his studies. As a dendrologist, he specialized in tree classification, focusing on gymnosperms, and expanding his academic boundaries from dendrology to forest geography. As a teacher of dendrology, he advocated cultivating virtue and talent, emphasized the cultivation of practical abilities, and implemented the feedback of scientific research in teaching. Professor Cheng Wan-chun regarded forest areas as the best laboratory of dendrology and personally visited forest areas such as West Tianmu Mountain in Zhejiang, Western Sichuan, and Lichuan in Hubei, collecting a large number of plant specimens, including types. Professor Cheng Wan-chun made many contributions to dendrology, discovering and naming one new family, five new genera, and 139 new species (including varieties). The most important contribution was the discovery of Metasequoia and the proposal of a classification system for gymnosperms. Table and Figures | Reference | Supplementary Material | Related Articles | Metrics | Comments（0）

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Advances in research of wildland-urban interface fires WANG Qiuhua, WANG Jin, LI Xiaona, MA Cheng, HONG Ruicheng, CAO Hengmao, GAO Zhongliang JOURNAL OF NANJING FORESTRY UNIVERSITY    2024, 48 (5): 1-10.   DOI: 10.12302/j.issn.1000-2006.202303047 Abstract （2424）   HTML （155）    PDF（pc） （1599KB）（4592）       Knowledge map    Save As the wildland-urban interface (WUI) becomes an increasingly important area of focus, the close relationship between human settlements and natural ecosystems such as forests has led to a high incidence of fires. Human activities play significant roles in the occurrence of fires in the WUI, and with rapid urbanization and the construction of forest cities, the complexity and severity of these fires have increased. This paper provides an overview of research progress on fires in the WUI, through literature analysis and case studies. At present, the concept of the WUI in China lacks clarity and standardization, highlighting the need for further research in this area. Future research should focus on expanding the database of interface fire cases and integrating satellite monitoring systems, video surveillance, and big data platforms to establish an early warning and monitoring system for the WUI. In addition, strengthening the research on fire behavior simulation and remote sensing monitoring, especially UAV fire behavior detection technology research on fire behavior simulations and remote sensing monitoring of WUI and unmanned aerial, remote-sensing monitoring and other new technologies will be crucial for providing effective solutions for fire prevention and control in the WUI. This will also contribute to the improvement of management measures, standards, and risk reduction strategies. Overall, the emphasis on new technologies and scientific research will provide a solid foundation for the management and reduction of fire risks in the WUI. Table and Figures | Reference | Supplementary Material | Related Articles | Metrics | Comments（0） Cited:

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A review on the taxonomy study of Prunus subgen. Cerasus (Mill) A. Gray YI Xiangui, LI Meng, WANG Xianrong JOURNAL OF NANJING FORESTRY UNIVERSITY    2024, 48 (3): 46-57.   DOI: 10.12302/j.issn.1000-2006.202405008 Abstract （3044）   HTML （224）    PDF（pc） （1729KB）（4481）       Knowledge map    Save Reviewed and summarized the research history of the taxonomy of the subgenus Prunus subgen. Cerasus, provided an overview of major classification systems of the subgen. Cerasus. Summarized the advances in experimental taxonomy studies on the subgen. Cerasus, It is found that morphological markers play an important role in the classification of subgen. Cerasus. SSR marker studies can provide evidence for discussions on interspecific and intraspecific relationships within the subgen. Cerasus, DNA sequence markers have made important achievements in the study of subgen. Cerasus classification, essentially clarifying the phylogenetic relationships within the subgen. Cerasus. Integrated the latest data on phylogeny and geographic distribution of the subgen. Cerasus, outlined the main framework of the phylogeny of the subgen. Cerasus, speculation that the origin of this subgenus is from the Himalayan region to southwestern China or the Mediterranean region, summarized the main migration routes of the subgen. Cerasus. By combining literature and specimen data, field surveys and recent research conclusions, a total of 76 species of the subgen. Cerasus (including 11 varieties) were listed in the world species catalog, and statistical analysis was conducted on the main distribution areas and groups of the subgen. Cerasus; proposed classification viewpoints for the P. serrulata complex, P. subhirtella complex, and other controversial groups. A comprehensive analysis of the status of the taxonomy of the subgen. Cerasus, suggesting that more in depth research is needed on the complex and controversial groups within the subgen. Cerasus, as well as resource surveys and classification in the central and western regions; exploring combinations of multiple species, populations, and omics at a large scale is an important direction for the taxonomy research of the subgen. Cerasus. Table and Figures | Reference | Supplementary Material | Related Articles | Metrics | Comments（0） Cited:

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Community classification, structures and species diversity characteristics of Pinus massoniana and P. hwangshanensis in the eastern China FAN Mingyang, HU Meng, YNAG Yuan, FANG Yanming JOURNAL OF NANJING FORESTRY UNIVERSITY    2024, 48 (1): 47-58.   DOI: 10.12302/j.issn.1000-2006.202210029 Abstract （3313）   HTML （86）    PDF（pc） （2167KB）（3860）       Knowledge map    Save 【Objective】 Pinus massoniana is the main coniferous tree species in subtropical China and P. hwangshanensis is the main constructive species in subtropical mid-montane region of the eastern China. Both species coexist at horizontal level but exhibit distinct vertical distributions. The objective of this study is to investigate the distribution patterns of P. massoniana and P. hwangshanensis forests and provide a theoretical basis for the scientific management and conservation of these forest resources. 【Method】 The study was focused on eight typical distribution areas in the eastern subtropical region of China. Non-metric multidimensional scaling analysis (NMDS) and multivariate regression trees (MRT) were employed to explore the differences in community structure and the main influencing factors between the two pine forests. Additionally, a linear mixed-effects model was used to quantify the response of species diversity indices to abiotic factors. Based on the principles for compiling the Vegegraphy of China, a preliminary quantitative classification of P. massoniana and P. hwangshanensis forests was performed. 【Result】 Significant differences were observed in the community structures of P. massoniana and P. hwangshanensis forests, with elevation identified as the primary influencing factor. Mean annual temperature had a significant effect on species richness within both communities, while mean annual precipitation had the most pronounced impact on overall species richness. Elevation exerted a significant influence on the evenness of the two communities. The preliminary vegetation classification resulted in the identification of six associations for P. massoniana forest and five associations for P. hwangshanensis forest. 【Conclusion】 Altitude variations shape the differences in community structure between P. massoniana and P. hwangshanensis forests and directly or indirectly influence species diversity in these communities. The vegetation classification highlights the diversification of vegetation types in the two pine forests and provides a reference for future classification efforts. Table and Figures | Reference | Supplementary Material | Related Articles | Metrics | Comments（0） Cited:

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Temperature, precipitation and runoff prediction in the Yangtze River basin based on CMIP 6 multi-model HE Xu, MIAO Zimei, TIAN Jiaxi, YANG Liu, ZHANG Zengxin, ZHU Bin JOURNAL OF NANJING FORESTRY UNIVERSITY    2024, 48 (2): 1-8.   DOI: 10.12302/j.issn.1000-2006.202203028 Abstract （6347）   HTML （428）    PDF（pc） （2585KB）（3709）       Knowledge map    Save 【Objective】 This research aims to explore the impact of future climate change on predicted runoff trends in the Yangtze River basin and provide a basis for early flood warning and prevention measures in the Yangtze River basin and other regions. 【Method】 Temperature, precipitation and runoff in the Yangtze River basin from 1961 to 2014 were evaluated by using the multi-mode set average (MME) of the international coupled model intercomparison project phase 6 (CMIP 6) and the SWAT hydrological model and predicted under SSP1-1.9, SSP1-2.6, SSP2-4.5, SSP3-7.0 and SSP5-8.5 emission scenarios from 2020 to 2099.【Result】 (1) Compared with the single model, MME showed better performance in simulating temperature and precipitation during historical periods, with a correlation coefficient with the observation value was >0.90. Further, MME simulated the spatial distribution of temperature and precipitation well. (2) The MME analysis showed that during 2020 and 2099, temperature and precipitation increases in the Yangtze River basin under all scenarios were <50% and <20%, respectively. Simulated temperature under the SSP5-8.5 scenario was 1.23 ℃ higher than that under the SSP1-1.9 scenario, and 0.99 ℃ higher than that under the SSP1-2.6 scenario. (3) Overall, future annual runoff of the entire Yangtze River basin increased significantly and reached 40 380 m3/s under the SSP5-5.8 scenario at the end of the 21st century.【Conclusion】 Temperature, precipitation and runoff in the Yangtze River basin are predicted to increase in the future, whereas flood disasters under low emission scenarios are relatively less likely. Table and Figures | Reference | Related Articles | Metrics | Comments（0） Cited:

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Mapping regional forest aboveground biomass from random forest Co-Kriging approach: a case study from north Guangdong ZHOU Youfeng, XIE Binglou, LI Mingshi JOURNAL OF NANJING FORESTRY UNIVERSITY    2024, 48 (1): 169-178.   DOI: 10.12302/j.issn.1000-2006.202202015 Abstract （2605）   HTML （42）    PDF（pc） （2806KB）（3439）       Knowledge map    Save 【Objective】 Forest aboveground biomass (AGB) is an important indicator for evaluating forest ecosystem health status and carbon sink potential. Accurate and quick mapping regional forest AGB has become intensively researched in forest ecosystem status assessment and global climate change studies in recent years. The major objective of this study was to develop a framework for improving the mapping accuracy of AGB in a subtropical forested area with complex terrain. 【Method】 Spectral features, textural indices, backscattering coefficients, and topographical variables were derived from Landsat 5 TM, ALOS-1 PALSAR-1 data and STRM DEM. Next, in tandem with national forest inventory plot measurements, a random forest/Co-Kriging framework that combines the advantages of random forest (RF) and a geostatistical approach was proposed to map AGB in northern Guangdong Province. 【Result】 The experimental results showed that the ordinary Kriging (OK) and Co-Kriging (CK) were able to predict the distribution of the RF-predicted AGB residuals. The predicted structured components of the residuals adding onto the RF predictions could improve the mapping accuracy of AGB to some extent. After the validation of the independent 20% dataset, the determination coefficient between the predictions and the observations increased from 0.46 (RF) to 0.51 (RFOK) and to 0.57 (RFCK). The root mean square error decreased from 32.48 to 31.58 and to 29.80 t/hm2 accordingly. The mean absolute error decreased from 27.28 to 26.63 and to 25.12 t/hm2. Overall, co-Kriging, which considers elevation as a co-variable, was better than ordinary Kriging in predicting AGB residuals. 【Conclusion】 The RFCK framework provides an accurate and reliable method to map subtropical AGB with complex topography. The resulting AGB maps contribute to targeted forest resource management and promote forest carbon sequestration and sustainable forest management under global warming scenarios. Table and Figures | Reference | Supplementary Material | Related Articles | Metrics | Comments（0） Cited:

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Effects of vegetation distribution on the carbon neutrality performance of urban green spaces YANG Yunfeng, YU Chunhua JOURNAL OF NANJING FORESTRY UNIVERSITY    2024, 48 (2): 209-218.   DOI: 10.12302/j.issn.1000-2006.202206031 Abstract （4103）   HTML （166）    PDF（pc） （2291KB）（3137）       Knowledge map    Save 【Objective】 To provide a theoretical reference for urban green space construction under the “Dual Carbon” goal, we established a carbon neutrality performance evaluation system and analyzed the impacts of vegetation distribution on the carbon neutrality performance of green spaces. 【Method】 Based on life cycle assessments, green space construction was divided into three stages: material production and transportation, site construction and planting, and green space operation and maintenance, which were combined with open, semi-open, covered and closed vegetation types. Carbon emissions and sink simulations were performed to analyze the carbon neutrality performance.【Result】 When the vegetation type changed from openness to closedness, the total carbon emissions increased rapidly and the trend accelerated. The proportions of carbon sources in the three stages decreased, leveled out and increased, respectively. The total carbon sink and net carbon neutrality both increased gradually. The number of years of carbon neutrality decreased gradually, from 43.9 years for open vegetation to 24.6 years for closed vegetation. These trends implied that there was a limit to the degree of vegetation shading for improving the carbon neutrality performance.【Conclusion】 Vegetation type clearly has an impact on the carbon neutrality performance. In terms of carbon sources, strategies such as reducing machinery use, selecting environmentally friendly materials, controlling construction damage, and improving energy utilization efficiency are suggested. For carbon sinks, strategies such as selecting tree species that have dominant local carbon sinks, adjusting the structures of vegetation communities, and regulating and managing green spaces along with life cycles are suggested. Ultimately, we postulate that green space carbon neutrality performance can be achieved by adapting to local conditions. Table and Figures | Reference | Supplementary Material | Related Articles | Metrics | Comments（0）

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Taxonomy and diversity of the genus Cupressus: current status and recommendations LI Jialiang, WU Dayu, MAO Kangshan JOURNAL OF NANJING FORESTRY UNIVERSITY    2024, 48 (3): 36-45.   DOI: 10.12302/j.issn.1000-2006.202405017 Abstract （3677）   HTML （238）    PDF（pc） （2256KB）（2996）       Knowledge map    Save Cupressus L., the type of Cupressaceae family, is typified by Cupressus sempervirens L. Over the years, as many other species have been discovered and described, and with advances in phylogenetics and population genetics, the taxonomy and species diversity within the genus Cupressus have been subjects of continuous debate. Traditionally, the Cupressus sensu lato includes species from true Cypresses sensu stricto and New World cypresses (Hesperocyparis Bartel & R.A.Price), while the Cupressus s. s. comprises all Old World species except the Vietnamese golden cypress (Xanthocyparis vietnamensis Farjon & T.H.Nguyên) found in Vietnam. Christenhusz et al. defined the broadest interpretation of Cupressus (Cupressus sensu Christenhusz) which encompasses four groups: true cypresses (Cupressus s.s.), Vietnamese golden cypress, Nootka cypress (Callitropsis nootkatensis (D.Don) Oerst), and New World cypresses. These ideas have been challenged by recent phylogenomic studies. Recent studies have shown that Cupressus s.l. is non-monophyletic, Cupressus s.s. is monophyletic and forms a sister group with the genus Juniperus. The common ancestor of these two is a sister group of the common ancestors of the Xanthocyparis, Callitropsis and Hesperocyparis. Based on current research, the true cypresses should encompass 14 species, including one hybrid. This paper offers new perspectives on previous contentious taxonomic treatments, for instance, reclassifying Cupressus rushforthii Maerki & J.Hoch as a synonym of Cupressus austrotibetica Silba, and confirming that Cupressus × jiangeensis N. Zhao is a hybrid offspring of the Cupressus fallax Franco and Cupressus funebris Endlicher. Additionally, Cupressus ×wangii J.Hoch, Maerki & Rushforth has been reduced to a synonym of Cupressus × jiangeensis. To avoid confusion, it is recommended to rename the recently discovered tallest tree species in Bomi County, Cupressus austrotibetica, to “西藏高柏” (Xizang tall cypress) in Chinese, and the cypress predominantly found in Nepal, Cupressus torulosa D.Don ex Lamb., is referred to as “喜马拉雅柏” (Himalayan cypress) in Chinese, instead of “西藏柏木” (Xizang Cypress). To ensure accuracy and scientific validity in future studies on species delineation within the genus, we recommend integrating multidimensional data from morphology, genetics, ecology and biogeography. This approach will help the reducing of classification confusion and support biodiversity conservation efforts more effectively. Table and Figures | Reference | Supplementary Material | Related Articles | Metrics | Comments（0） Cited:

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Regulation of LBD12 transcription factor on wood formation in Populus trichocarpa GAO Yuan, SUN Jiatong, ZHOU Chenguang, CHIANG Vincent, LI Wei, LI Shuang JOURNAL OF NANJING FORESTRY UNIVERSITY    2024, 48 (1): 29-38.   DOI: 10.12302/j.issn.1000-2006.202301002 Abstract （588）   HTML （29）    PDF（pc） （4417KB）（2655）       Knowledge map    Save 【Objective】The formation of wood, one of the most important raw materials for pulp and energy, depends on a complex and precise transcriptional regulation process in which transcription factors figure prominently. In Populus trichocarpa, PtrLBD12 (lateral organ boundaries domain 12) is a transcription factor lying downstream of PtrbHLH186, a key regulator of wood formation. Hence, PtrLBD12 was studied in depth here to investigate its function in tree growth and wood formation.【Method】 To determine the role of the PtrLBD12 transcription factor in the growth and wood formation of poplar trees, we analyzed its expression characteristics, generated PtrLBD12 overexpressing plants of P. trichocarpa, and assessed the growth and wood formation traits of transgenic plants. (1) Xylem, phloem, and terminal bud and leaf samples of wild-type P. trichocarpa plants, cultivated in a greenhouse, were collected to extract their respective RNA. Next, transcriptome sequencing was done to analyze the patterns of differentially expressed genes in those distinct tissues, as well as their expression levels of PtrLBD12. (2) To clarify the expression pattern of the PtrLBD12 protein, its subcellular localization was investigated by using the transient transformation system of stem-differentiating xylem protoplasts of P. trichocarpa. (3) To create PtrLBD12-overexpressing plants, the Agrobacterium tumefaciens-mediated transformation system of P. trichocarpa was used, with transgenic plants identified at both the DNA and RNA level. (4) Plant stem height, ground (basal) stem diameter, number of stem nodes, and length of the 8th stem node of transgenic and wild-type plants were measured at 30, 60 and 90 days after planting. (5) The 2nd, 4th, 6th and 8th stem segments of overexpressing and wild-type greenhouse plants cultivated for 4 months were paraffin-sectioned. Their stem characteristics were then respectively observed via Safranin O/Fast Green and Toluidine Blue staining. LAS X V2.0 software was used to calculate the number of vessel and fiber cells, as well as average lumen area of vessel. (6) The relative expression levels of 22 monolignol biosynthetic pathway genes in the PtrLBD12-overexpressing plants were determined by using quantitative PCR and applying the 2△△Ct calculation.【Result】 (1) Transcriptome analysis of the xylem, phloem, and terminal bud and leaf tissues of P. trichocarpa revealed a higher expression level of PtrLBD12 in both the xylem and phloem. (2) Subcellular localization showed that PtrLBD12 was expressed in the nucleus, where transcription factors in general were found. (3) Three PtrLBD12 overexpressing transgenic lines of P. trichocarpa were obtained, whose relative expression levels were 40.91, 79.51 and 102.19. (4) Overexpressing PtrLBD12 adversely affected the normal growth and development of P. trichocarpa: plant height, ground stem diameter, number of stem nodes, and length of the 8th stem node all decreased significantly in transgenic plants vis-à-vis the wild type. (5) However, overexpression of PtrLBD12 did lead to significantly more vessel and fiber cells per unit of area in the stems of transgenic plants, but these vessels had smaller lumen area. Furthermore, the augmented expression of PtrLBD12 enhanced lignification of the plant stem. (6) Finally, PtrLBD12’s overexpression bolstered the expression levels of multiple genes in the monolignol biosynthetic pathway, namely PtrPAL1, PtrC4H1, PtrC4H2, PtrHCT6, PtrCSE, PtrCSE2, PtrCCoAOMT1, PtrCCoAOMT2, PtrCCoAOMT3, PtrCCR2 and PtrCAld5H1.【Conclusion】As the gene downstream of PtrbHLH186, a key regulator of wood formation in poplar, the LBD12 transcription factor is able to govern the expression of monolignol biosynthetic genes, change the mode of lignin deposition, alter the morphology of xylem cells, and thereby affect plant growth and development. Table and Figures | Reference | Supplementary Material | Related Articles | Metrics | Comments（0） Cited:

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Changes in pigment and coloration mechanism of leaves during the discoloration period of Pistacia chinensis XU Zhizhao, YANG Xiuyun, WANG Yichen, DU Shuhui JOURNAL OF NANJING FORESTRY UNIVERSITY    2024, 48 (2): 97-104.   DOI: 10.12302/j.issn.1000-2006.202210034 Abstract （3373）   HTML （197）    PDF（pc） （2215KB）（2582）       Knowledge map    Save 【Objective】 The changes of physiological substances related to the discoloration period of the leaves of Pistacia chinensis in autumn were studied to reveal the regularity between leaf color and content.【Method】 The experiment was conducted to quantify and analyze the changes in leaf color parameters, pigments, osmotic substances, total nitrogen and phosphorus contents and the key enzyme activities of P. chinensis.【Result】 During the discoloration period, the contents of chlorophyll and carotenoid in leaves continuously decreased, the content of anthocyanins increased, and the leaves turned red. Anthocyanins in the leaves of P. chinensis showed extremely significantly positive correlations with a* values, the ratio of carotenoid to chlorophyll and anthocyanin to chlorophyll, soluble sugar, free amino acid, phenylalanine ammonialyase(PAL) and anthocyanidin synthase(ANS) (P<0.01). Anthocyanins were positively correlated with dihydroflavonol-4-reductase(DFR) (P<0.05). Anthocyanins were negatively correlated with nitrogen(N) (P<0.05). Anthocyanins were extremely significantly negatively correlated with phosphorus(P) (P<0.01). 【Conclusion】 The anthocyanin/chlorophyll ratio and anthocyanin content in the leaves during the autumn discoloration period of P. chinensis are the material basis for leaf reddening in the middle stage of discoloration. Soluble sugar content and PAL enzyme activity are the key factors affecting color. Mineral elements (nitrogen and phosphorus) content in the discoloration period was significantly reduced, promoting anthocyanin synthesis and affecting leaf color. Table and Figures | Reference | Supplementary Material | Related Articles | Metrics | Comments（0） Cited:

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Effects of different shedding time on aroma and nutrients of Torreya grandis ‘Merrillii’ seed kernel WEI Xixing, HU Yuanyuan, ZHU Guangxia, YU Weiwu, ZHANG Zuying, WU Jiasheng, SONG Lili JOURNAL OF NANJING FORESTRY UNIVERSITY    2024, 48 (2): 51-60.   DOI: 10.12302/j.issn.1000-2006.202308024 Abstract （4287）   HTML （241）    PDF（pc） （2554KB）（2327）       Knowledge map    Save 【Objective】 The objectives of this study were to elucidate the effect of aril on the quality of Torreya grandis kernel, and compare the aroma components and nutrients of kernels with different peeling times. 【Method】 Aroma components of kernels were determined with different peeling times (0d, kernel sample with aril removed from seed on harvest day; 10CK, kernel sample with aril removed from seed on harvest day and stored at 90% relative humidity and 25 ℃ for 10 days; 10BLACK, kernel sample with aril removed from seed 10 days after harvesting) by headspace solid-phase microextraction and gas chromatography-mass spectrometry (SPME/GC-MS). The characteristic aroma components of kernels at different peeling times were detected, and differences in their nutrient content were also compared. 【Result】 (1) A total of 57 aroma components were identified under different treatments, including terpenes (16 species), alcohols (14 species), benzenes (8 species), aldehydes (6 species), esters (1 species), ketones (7 species), acids (2 species), and ethers (3 species), among which the content of terpenes was the highest. Principal component analysis showed that the main aroma components of the 0d and 10CK samples were terpene and benzene, respectively, whereas those of 10BLACK were ether, ketone, aldehyde, ester, alcohol, and acid compounds. (2) Venn plot analysis showed that the number of characteristic substances of 0d, 10CK and 10BLACK was 14, 10 and 16, respectively, among which 4-methyl-1-(1-methylethyl)-, Bicyclo[3.1.1]hept-3-en-2-ol, 4,6,6-trimethyl-, and Bicyclo[3.1.1]hept-3-en-2-one, 4,6,6-trimethyl-, (1S)- had a peculiar odor. (3) Compared to 0d samples, the crude fat, soluble sugar, and soluble protein content of 10CK samples was significantly higher (P<0.05), whereas the starch content was significantly lower (P<0.05). There was no significant difference in crude fat, soluble sugar, starch, and soluble protein content between 10BLACK and 10CK samples. 【Conclusion】 Compared to kernels from seed peeled off on harvest day, those peeled at 10 days after harvesting formed more abnormal odors. Therefore, T. grandis ‘Merrillii’ should be promptly peeled after picking, otherwise it will produce odorous aromatic substances that affect the flavor of its kernel. Table and Figures | Reference | Related Articles | Metrics | Comments（0） Cited:

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Plant hormones and metabolites response to feeding stimulation by pine caterpillar (Dendrolimus tabulaeformis) and leaf clipping control in Chinese pine (Pinus tabuliformis) ZHAO Ya’nan, SUN Tianhua, WANG Lifeng, XU Qiang, LIU Junxia, GAO Baojia, ZHOU Guona JOURNAL OF NANJING FORESTRY UNIVERSITY    2024, 48 (1): 219-226.   DOI: 10.12302/j.issn.1000-2006.202206014 Abstract （1443）   HTML （9）    PDF（pc） （1817KB）（2239）       Knowledge map    Save 【Objective】This experiment was conducted with the aim of defining changes in metabolic pathways in response to mandibulate insect feeding and providing references for the growth and protection of Chinese pine (Pinus tabuliformis).【Method】Pure P. tabuliformis forest in good growth status in Huangtuliangzi Forest Farm of Pingquan City, Chengde City, Hebei Province was the experimental field. Branches with consistent branch length and height above the ground in four directions were stimulated by ten pine caterpillars (Dendrolimus tabulaeformis) for feeding stimulation and leaf clipping control for mechanical damage. The pine needles were collected 3 cm below the chewing or cutting sites. The CK group received no treatment (0 h, recorded as 0 h), and 10 intact pine needles were collected. Metabolome and total flavonoid contents were measured in the needles at 0, 2 and 8 h after the different treatment modes. The plant hormones JA, SA, IAA and ABA were measured using needles at 0, 0.5, 1.0, 1.5, 2.0, 4.0, 6.0, and 8.0 h after different treatments.【Result】Analysis of metabolomics showed that the top three pathways mainly annotated and enriched for DAMs compared to 2.0 h after FS and LCC are flavonoid biosynthesis, amino acid metabolism, and arginine and proline metabolism; the top three pathways mainly annotated and enriched for DAMs compared to 8.0 h after FS and LCC are flavonoid biosynthesis, linoleic acid metabolism, and flavonoid and flavonol biosynthesis. Thus, D. tabulaeformis feeding stimulation can significantly induce the upregulation of flavonoid expression at the chewing sites of needles when compared to the leaf clipping control. The plant hormones, JA and IAA, showed expression trends consistent with those of the corresponding substances in the metabolome. A significant positive correlation between JA and SA, JA and IAA and IAA and ABA (P< 0.05) was observed. 【Conclusion】Thus, the flavonoid pathway is one of the main pathways involved in resistant formation in conifers. Simple damage mechanisms did not induce significant differences in JA, IAA and ABA; thus, JA, IAA and ABA are involved in the development of resistance and growth during biotic stress. Table and Figures | Reference | Supplementary Material | Related Articles | Metrics | Comments（0）

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The potential application of GGPPS gene in improving plant color and aroma traits WANG Lianggui, ZENG Guimin, YANG Xiulian, YUE Yuanzheng JOURNAL OF NANJING FORESTRY UNIVERSITY    2024, 48 (1): 1-10.   DOI: 10.12302/j.issn.1000-2006.202305025 Abstract （915）   HTML （73）    PDF（pc） （3516KB）（2207）       Knowledge map    Save Color and aroma are important factors that affect the ornamental quality of garden plants and have a decisive impact on their ornamental value. Carotenoids are important pigment substances in plants and are key aromatic components in plants. The geranylgeranyl pyrophosphate synthase gene (GGPPS), which is located at a critical intersection of the two synthesis pathways, has a considerable impact on the formation of plant color and aromatic-related metabolites. This study reviews the structure, classification, and evolutionary clustering of GGPPS proteins, transcriptional regulation of GGPPS genes, and other regulatory factors. We further summarize the mechanism by which GGPPS genes affect the formation of plant color and aroma and explore their potential applications in improving plant color and aroma traits. The aim of this study is to provide new genetic resources and research ideas for the genetic improvement of ornamental plant traits. Table and Figures | Reference | Related Articles | Metrics | Comments（0）

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Changes of non-structured carbohydrate and starch metabolizing enzyme in bulbs of Lycoris radiata within the annual growth cycle WEI Xuying, ZHANG Yao, MA Meixia, JIANG Xueru, CHEN Huiting, WU Jing, YANG Yu, CAI Junhuo JOURNAL OF NANJING FORESTRY UNIVERSITY    2024, 48 (1): 106-114.   DOI: 10.12302/j.issn.1000-2006.202201008 Abstract （534）   HTML （27）    PDF（pc） （1979KB）（2195）       Knowledge map    Save 【Objective】The study investigated inherent relationship between the unique growth rhythm of Lycoris spp. and changes in non-structural carbohydrates (NSC) and related metabolic enzyme activities. The aim was to provide a research basis for studies of the intrinsic physiological mechanism of L. spp. unique flowering habits and summer leaf dormancy.【Method】In 4-year-old clonal bulbs of L. radiata, the contents of six NSC and nine starch metabolism activities were determined by spectrophotometric and micrometric methods at six growth stages, including leafing-out period, rapid leaf extension period, leaf maturity period, leaf withering period, dormancy period and flowering period.【Result】The NSC content in bulbs at different developmental stages was significantly different. Total NSC, soluble sugar, fructose, and reductive sugar content were the highest in the leaf maturity period. Starch and sucrose contents were the highest in the leaf withering period. The peak starch accumulation lagged behind that of soluble sugars. Significant differences were evident in the activities of nine metabolic enzymes in bulbs at different developmental stages (P < 0.01). During the same period, the activity of ADP-glucose pyrophorylase (AGP) was significantly higher than those of the other eight enzymes. The activities of β-amylase (β-AL) and starch branching enzyme (SBE) were always higher than α-amylase (α-AL) and starch debranching enzyme(DBE), and the activities of soluble starch synthase (SSS) and sucrose phosphate synthase (SPS) were respectively higher than that of granule-bound starch synthase (GBSS) and sucrose synthase (SuS), which corresponded with the significantly higher fructose content in bulbs in different periods. Sucrose and starch contents were negatively correlated with SBE activity and positively correlated with GBSS activity. The opposite correlations were observed for fructose and maltose. In addition, sucrose content was also negatively correlated with the activity of β-AL.【Conclusion】The change of NSC content in bulbs was positively correlated with the vigorous state of leaf growth. Starch accumulation in bulbs was mainly positively regulated by AGP and SPS and negatively regulated by SSS, SBE and DBE. The accumulation of sucrose in bulbs is mainly from amylolysis, rather than translocation of photosynthetic organs. In addition, the fructose content of bulbs was significantly higher than the sucrose content during the annual growth cycle, which may be related to the unique biological characteristics of L. radiata. Table and Figures | Reference | Supplementary Material | Related Articles | Metrics | Comments（0） Cited:

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Research on forest fire risk evaluation based on machine learning algorithm LI Shixin, ZHANG Fuquan, LIN Haifeng JOURNAL OF NANJING FORESTRY UNIVERSITY    2023, 47 (5): 49-56.   DOI: 10.12302/j.issn.1000-2006.202202004 Abstract （1543）   HTML （62）    PDF（pc） （3099KB）（2189）       Knowledge map    Save 【Objective】 Forest fire risk maps are necessary to improve effective patrols and optimize the scientific layout of limited fire prevention resources. This study uses machine learning algorithms to construct forest fire occurrences based on terrain, human activities, vegetation, and meteorological factor data.【Method】With Jiushan Mountain in Chuzhou city in Anhui province as the research object, we extracted the following potential driving factors: slope, elevation, aspect, distance to settlement, distance to road, topographic wetness index, normalized difference vegetation index and temperature of the study area, evaluated the driving factors of fire occurrence, and then divided the potential driving factors into topography, human activities, vegetation, meteorological factors, and other four categories. Historical fire points in the forest area were extracted from the sentinel fire products. A prediction model for forest fire occurrence was then constructed using a machine learning algorithm. Finally, the accuracy of the models was evaluated using a confusion matrix and receiver operating characteristic curves. 【Result】We found that vegetation, temperature and distance to the road are the main driving factors of forest fires in the study area. The ROC curves of the two models showed that the Logistic regression prediction model had an accuracy of 71.07%, where the area under the curve was 0.717 2. Meanwhile, the random forest model had a better accuracy, with an accuracy of 84.91% and an area under the curve of 0.850 1.【Conclusion】The random forest model exhibits a better predictive ability than that does the logistic regression model. Furthermore, the generated forest fire risk map shows that 11.91% (29.36 km2) of the study area is at a high or extremely a high risk. If utilized, this forest fire risk map can effectively help forest fire protection managers implement appropriate measures to protect forest resources in Jiushan Mountain. Table and Figures | Reference | Supplementary Material | Related Articles | Metrics | Comments（0） Cited:

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Effect of stand density on radial growth-climate relationship of Larix gmelinii HAN Xinyu, GAO Lushuang, QIN Li, PANG Rongrong, LIU Mingqian, ZHU Yihong, TIAN Yiyu, ZHANG Jin JOURNAL OF NANJING FORESTRY UNIVERSITY    2024, 48 (2): 182-190.   DOI: 10.12302/j.issn.1000-2006.202209007 Abstract （3203）   HTML （169）    PDF（pc） （2250KB）（2166）       Knowledge map    Save 【Objective】 To develop a sustainable management plan for Larix gmelinii, which is influenced by climate change, it is crucial to understand the dynamic relationship between radial growth and climate in forests with different tree densities.【Method】 Based on the stand density index, nine plots with three density levels (low, middle, high) were established in the central and northern Greater Khingan Mountains. Tree cores of L. gmelinii were collected during a field investigation. The Mann-Kendall test method was used to determine the turning point of temperature in the study area. To examine the radial growth trend of L. gmelinii, negative exponential function detrending and a linear function fitting were applied. Then, a Pearson correlation and sliding correlation were used to analyze whether the relationship between the radial growth and climate factors under each stand density remained stable after the temperature turning point.【Result】 The radial growth of L. gmelinii displayed trends of both enhancement and decline after the temperature turning point. The proportion of declining trees increased with increasing stand density. The growth of L. gmelinii was strongly inhibited when the stand density was high. Its average growth change rate reached -25% during 1988-1990, indicating a serious growth decline. Instead, the L. gmelinii trees in low density plots maintained a 54% growth enhancement ratio. Stand density may also influence the response of L. gmelinii growth to climate. Under a high stand density, the L. gmelinii growth of the decline group was positively correlated with the standardized precipitation evapotranspiration index in August (P<0.05) and negatively correlated with summer temperature (P<0.05), but under a low stand density, the growth of L. gmelinii was positively correlated with temperature. With the warming and drying trend in the study area, the relationship between tree growth and temperature shifted from positive to negative with increasing stand density.【Conclusion】 The proportion of declining trees increased with increasing stand density after the significant change of temperature. The impact of water limitation on growth was alleviated at a low stand density, while the trees in high density plots were more sensitive to climate factors. Reducing the stand density could mitigate the negative impacts of climate warming on the growth of L. gmelinii. Therefore, adjusting stand density is a necessary management operation to slow the declining trend of L. gmelinii. Table and Figures | Reference | Supplementary Material | Related Articles | Metrics | Comments（0） Cited:

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The spatio-temporal characteristics of soil erosion in orchards of Dalian City based on the CSLE model JI Xinyu, YU Yue, ZHANG Sifan, LIU Yuanyuan JOURNAL OF NANJING FORESTRY UNIVERSITY    2024, 48 (3): 117-124.   DOI: 10.12302/j.issn.1000-2006.202304015 Abstract （2542）   HTML （98）    PDF（pc） （3079KB）（2142）       Knowledge map    Save 【Objective】 The orchards in Dalian City suffer from soil erosion due to vigorous developmental activities. This study aimed to quantitatively analyze the status of soil erosion, determine the spatio-temporal characteristics of soil erosion in orchards in Dalian City, and explore the key factors that influence soil erosion. The results can provide significant insights for the healthy development and ecological protection of the orchard industry in Dalian City. 【Method】 The characteristics of soil erosion in orchards in Dalian City were assessed by using the Chinese soil loss equation (CSLE) model, based on geographic big data available online. The results were visually interpreted, and the dynamic changes and factors influencing soil erosion in the study area were subsequently analyzed. 【Result】 The area of soil erosion constituted approximately 40% of the total area of Dalian City, and the erosion was serious in the northern and southern mountainous and hilly regions. The average soil erosion modulus of the orchards in Dalian City was 1 230.29, 1 150.95, 2 311.36, 6 384.55, 3 399.60 and 3 484.24 t/(km2·a) in 2015, 2016, 2017, 2018, 2019 and 2020, respectively. Analysis of the intensity of soil erosion primarily revealed micro and slight erosion. Strong and above grade erosion was primarily observed in Ganjingzi, Jinzhou, and Lüshunkou District. Soil erosion was primarily observed in slope grades below 25° and in regions with rainfall grades ranging between 500 and 900 mm. The finding revealed that greenhouse coverage could reduce soil erosion in greenhouse orchards and open field/facility orchards, and vegetation coverage could effectively reduce soil erosion in open field orchards. 【Conclusion】 Soil erosion in the orchards in Dalian City exhibits obvious spatial distribution characteristics in that the intensity of erosion is high in the south and low in the north area. The successful control of soil erosion in orchards and the efficient promotion and sustainable development of the orchard industry can be achieved in future by increasing the area of greenhouse coverage, increasing the vegetation coverage of outdoor greenhouses, and selecting the location of orchards reasonably. Table and Figures | Reference | Supplementary Material | Related Articles | Metrics | Comments（0） Cited:

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Effects of BpGLK1 interference expression on leaf color and growth of Betula pendula ‘Dalecarlica’ YANG Yunli, CAO Li, WANG Yang, GU Chenrui, CHEN Kun, LIU Guifeng JOURNAL OF NANJING FORESTRY UNIVERSITY    2024, 48 (1): 18-28.   DOI: 10.12302/j.issn.1000-2006.202207018 Abstract （594）   HTML （27）    PDF（pc） （2651KB）（2009）       Knowledge map    Save 【Objective】 Betula pendula ‘Dalecarlica’ is an European white birch species found in the northeast of China. After entering the reproductive growth stage, the pistil development is normal and can pollinate with other European white birch or white birch species to produce offspring; however, the stamens are aborted and cannot produce pollen. Because of the beautiful tree posture, clean white bark, and notable leaf edges with cracks, B. pendula ‘Dalecarlica’ has high ornamental value and is gradually being used in street greening to enrich plant species in urban landscaping. However, with improvements in the living standards of urban residents, diverse and colorful forms of greenery have become favored. Therefore, changing the leaf color of these tree species will enhance the application prospects in landscape architecture. The golden2-like (GLK) gene belongs to the GARP transcription factor superfamily of Myb transcription factors. GLK transcription factors are involved in regulating plant chloroplast development and hormone signaling, and play important roles in plant disease resistance, nutrient synthesis and leaf senescence, indicating that GLK transcription is the key gene for reforming plant leaf color. GLK transcription factors mainly regulate light capture and chlorophyll biosynthesis-related gene expression during plant chloroplast development as well as fruit skin color, thereby affecting chlorophyll synthesis and chloroplast development. Therefore, to cultivate colorful tree species for urban landscaping and scenery preferences, a molecular-based breeding method was used to create the golden leaf B. pendula ‘Dalecarlica’. 【Method】 B. pendula ‘Dalecarlica’ stem segments were used. The previously constructed 35S::BpGLK1-RNAi vector was introduced into the B. pendula ‘Dalecarlica’ genome via the agrobacterium method. DNA and RNA were extracted from wild type (WT) and resistant transgenic lines and were measured. The BpGLK1 interfering expression lines of B. pendula ‘Dalecarlica’ were expanded and transplanted. The leaf color, photosynthetic pigments, photosynthetic parameters, plant height growth, and gene expression characteristics of the BpGLK1 interfering expression lines of B. pendula ‘Dalecarlica’ were determined. 【Result】 Resistant calluses were obtained after co-cultivation on a selective medium for 30 days. The calluses were differentiated and cultured to obtain resistant adventitious buds, which were inoculated into a rooting medium. Adventitious roots were grown and transgenic B. pendula ‘Dalecarlica’ mutants were obtained. Eight herbicide-resistant regenerated transformation lines (RE1-RE8) were obtained following transplantation into the seedling trays. Using the total DNA of eight transgenic B. pendula ‘Dalecarlica’ leaves as templates and the pFGC5941-GLK1 plasmid as positive control, PCR amplification was performed on the forward target sequence and complementary sequence of the BpGLK1 gene, indicating that the interfering fragment of BpGLK1 gene and Bar gene have been integrated into the genome of the transgenic B. pendula ‘Dalecarlica’. The relative BpGLK1 expression in these transgenic lines was downregulated, with RE1-RE4 being the largest, whereas the RE6-RE8 decrease was relatively small. Among the eight transgenic lines, RE1-RE5 were yellow-leaf lines and RE6-RE8 were green-leaf lines. The leaf color parameters and relative chlorophyll content of 1-year-old transgenic lines were investigated in the transplanted fields, and the results indicated that compared with the WT and green-leaf lines RE6-RE8, the yellow-leaved strains RE1-RE5 showed significantly higher leaf color parameters L* and b* and lower chlorophyll a and b contents (P<0.05); however, the ratio of chlorophyll a to b exhibited an increasing trend. This result showed that low BpGLK1 expression significantly improved the leaf brightness of the transgenic lines. The Fv/Fm value of the transgenic strains was higher or significantly higher than that of the WT strain, with the yellow line RE2 having the highest Fv/Fm value, which was 1.39% higher than that of the WT strain. However, there was no significant difference in net photosynthetic rate (Pn) between transgenic lines and WT plants. Plant heights of the transgenic lines in the year of transplantation were surveyed. Plant height analysis showed that the four transgenic lines RE1, RE2, RE4 and RE6 were significantly higher than those in the WT, and there was no significant difference between the three transgenic lines RE3, RE5, RE7 and the WT. Only the height of line RE8 was significantly lower than that of WT. Based on RNA-seq, four genes, BpCOL, BpLCHⅡ, BpPDS, were significantly down-regulated. qRT-PCR analysis of these four genes indicated that they were significantly downregulated in RE1-RE3 expression. 【Conclusion】 The introduced GLK1 interfering target sequence reduced the BpGLK1 expression in transgenic B. pendula ‘Dalecarlica’. The obtained yellow-leaved B. pendula ‘Dalecarlica’ lines have potential applications in landscaping. Table and Figures | Reference | Related Articles | Metrics | Comments（0）

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Improved time series models based on EMD and CatBoost algorithms: taking PM2.5 prediction of Dalian City as an example ZHAO Lingxiao, LI Zhiyang, QU Leilei JOURNAL OF NANJING FORESTRY UNIVERSITY    2024, 48 (3): 268-274.   DOI: 10.12302/j.issn.1000-2006.202205005 Abstract （860）   HTML （10）    PDF（pc） （2848KB）（2000）       Knowledge map    Save 【Objective】 The study aims to address the problem of low accuracy in traditional PM2.5 concentration time series prediction, and to reduce the impact of nonlinearity, high noise, instability and volatility on the prediction of PM2.5 time series, to predict PM2.5 concentration more accurately. 【Method】 The haze PM2.5 data of Dalian City from January 1, 2014 to January 31, 2022 was used as an example. In this study, a hybrid machine learning time series model with the combination of empirical modal decomposition (EMD), classification boosting (CatBoost) and autoregressive integrated moving average model (ARIMA) was proposed. It was compared with the traditional autoregressive model (AR), ARIMA and the hybrid model with only the EMD method. 【Result】 The hybrid model EMD-CatBoost-ARIMA improved the root mean square error (RMSE) of the original sequence by 20.76%, the mean absolute error (MAE) by 17.40%, and the theil inequality coefficient (TIC) by 29.17%. 【Conclusion】 For reconstructed sequences with high entropy values, the EMD decomposition method and CatBoost algorithm can significantly improve the prediction performance of PM2.5 time series models. Compared with the traditional time series models, the EMD-CatBoost-ARIMA model has higher performance in PM2.5 concentration prediction. Table and Figures | Reference | Supplementary Material | Related Articles | Metrics | Comments（0） Cited:

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Affecting factors analysis of functional diversity at different forest strata in an old growth forest community in Yachang Natural Reserve WANG Yaoyi, WANG Hongxiang, WANG Yongqiang, ZENG Wenhao, YE Shaoming JOURNAL OF NANJING FORESTRY UNIVERSITY    2024, 48 (5): 28-38.   DOI: 10.12302/j.issn.1000-2006.202208030 Abstract （1708）   HTML （103）    PDF（pc） （2573KB）（1958）       Knowledge map    Save 【Objective】 Functional diversity is crucial for forest biodiversity protection and maintenance of ecosystem stability. Exploring the characteristics and causes of functional diversity variation at different stratum levels will assist in understanding the maintenance mechanisms of biodiversity and plant community assembly processes. 【Method】 Leaf traits and environmental factors were collected from forest plot data from an 1.6 hm2 evergreen broadleaved forest in Guangxi Yachang Orchidaceae National Natural Reserve. K-means partitioning and Gaussian kernel density estimation were used for stratification. The direct and indirect effects of species diversity and environmental factors (light, topography, and soil) on functional diversity were explored in different forest strata using structural equation models. 【Result】 The diversity indices of the understory were greater than those of the canopy (P<0.05). Species diversity had a significant direct impact on all four functional diversity indices in the understory layer, whereas only the functional richness index (FRic) and quadratic entropy (RAOQ) indices were affected directly by species diversity in the canopy layer (P<0.05). A significant indirect effect (β = 0.278, P<0.01) of canopy openness on FRic index and a direct effect (β = -0.593, P<0.01) of canopy openness on functional evenness index (FEve) were found for understory trees. Topographic factors affected canopy functional diversity. Specifically, there was a relatively significant direct effect of aspect on FEve (β = -0.420, P<0.01) and RAOQ (β = -0.300, P<0.05) indices for canopy trees. Soil factors mainly affected the functional diversity of different forest layers through species diversity. Soil total phosphorus, available phosphorus, alkaline hydrolysis nitrogen, and available potassium content had a greater effect on the functional diversity of the understory, whereas soil total potassium content affected the FRic and RAOQ indices of the canopy. 【Conclusion】 There were marked differences in the characteristics of functional diversity at different forest stratum in the study area. Functional diversity was mainly affected by species diversity, canopy openness, and soil nutrients of understory plants, whereas topographic factors determined the functional diversity of the canopy layer. This study reveals the effects of biological and abiotic environmental factors on functional diversity across different forest layers and expands the understanding of the diversity of vertical stratification. The findings provide a further reference for biodiversity protection in natural forests. Table and Figures | Reference | Related Articles | Metrics | Comments（0）

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Characteristics of fuel load distribution in typical subtropical forest types LI Jianhua, XIA Honglu, TANG Weiping, HUANG Han JOURNAL OF NANJING FORESTRY UNIVERSITY    2023, 47 (5): 57-64.   DOI: 10.12302/j.issn.1000-2006.202302022 Abstract （958）   HTML （14）    PDF（pc） （2321KB）（1897）       Knowledge map    Save 【Objective】The fuel load is important for forest fire management. This study investigated the distribution of fuel load and analyzed the relationship between the per unit area fuel load components and volumes, within the tree layer among subtropical forest types, to provide scientific references for sustainable forest management. 【Method】Forest fire survey and supplementary investigation data were taken from Huzhou City, Zhejiang Province. Nine typical subtropical forest types were chosen as research objects. The fuel load per unit area of each component of different forest types was measured and calculated by quadratic investigation and drying methods. One-way ANOVA was used to test for differences of the fuel load per unit area among forest types and components. The linear or nonlinear correlation fitting was carried out on the fuel load per unit area of the components and the volume per unit area of the tree layer of typical forest types to analyze their correlation.【Result】The amount of the fuel load per unit area of tree layer in most forest types was significantly higher than that in the fallen dead wood layer (P< 0.05), and the fallen dead wood layer was significantly higher than other components such as the shrub layer (P< 0.05). However, the fuel load per unit area of the fallen dead wood layer in Phyllostachys edulis monoculture forests was significantly higher than that of other components (P< 0.05). The fuel load per unit area in the tree layer of Quercus spp. forests, Schima superba forests, and coniferous and broad-leaved mixed forests were higher than that of other forest types. The fuel load per unit area of the litter layer in coniferous and broad-leaved mixed forests, Schima superba forests, and other soft broad-leaved forests were higher than that of other forest types. The results of the regression analysis showed that for most forest types, there was a significant linear positive correlation between fuel load per unit area and volume per unit area of tree layer. Among them, Quercus spp. forests have the highest correlation (R2=0.89). Nevertheless, the amount of the fuel load per unit area in the shrub layer and herb layer in most forest types decreased with the increase of the amount of volume per unit area.【Conclusion】The management of subtropical forest fuel loads should take full account of the differences in the distribution characteristics of different forest types and the interrelationship among different components. The composition of tree species in the canopy layer has a significant impact on the distribution of forest surface fuels. The storage volume per unit area of tree layer is closely related to the fuel load per unit area of tree layer and is an important reference indicator for the analysis and prediction of fuel loads of forest components. Table and Figures | Reference | Related Articles | Metrics | Comments（0） Cited:

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Extraction of aquatic vegetation in Hongze Lake National Wetland Park based on Sentinel-1 and Sentinel-2 images HAN Sen, RUAN Renzong, FU Qiaoni, XU Hanwei, HENG Xuebiao JOURNAL OF NANJING FORESTRY UNIVERSITY    2024, 48 (2): 19-26.   DOI: 10.12302/j.issn.1000-2006.202212016 Abstract （3387）   HTML （275）    PDF（pc） （3960KB）（1892）       Knowledge map    Save 【Objective】 The objective of this study was to explore the extraction of spatio-temporal distribution of aquatic vegetation in lake wetlands using Sentinel-1 and Sentinel-2 data. 【Method】 Hongze Lake National Wetland Park was chosen as the research area. Based on the combination of Sentinel-2 MSI images and Sentinel-1 SAR images, the object-oriented image analysis was used. The feature set was constructed by using EVSI, NDVI, SR feature index and contextual features between objects, as well as differences in the backscatter coefficients of the SAR images corresponding to differences in the height of the emergent vegetation types. A decision-tree model was established at the object level to classify the wetland, and the spatio-temporal distribution of the aquatic vegetation and the emergent vegetation in the Hongze Lake National Wetland Park was acquired. 【Result】 The classification accuracy and the Kappa coefficient of aquatic vegetation were observed to be 89% and 0.85, respectively, and that of the emergent vegetation was 85.2% and 0.76, respectively. The results showed that, compared with the results of the pixel-based analysis method, the accuracy of object-based image analysis was higher. The wetland aquatic vegetation was dominated by submerged and emergent vegetation; among the emergent vegetation, lotus leaves and reeds were dominant. 【Conclusion】 The methods proposed in this study were feasible, and the results could provide a scientific basis for managers and planners of wetlands. Table and Figures | Reference | Related Articles | Metrics | Comments（0） Cited:

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Associations between urban green space accessibility and mental health of residents from the perspective of socio-economic status YANG He, MI Feng JOURNAL OF NANJING FORESTRY UNIVERSITY    2024, 48 (1): 248-256.   DOI: 10.12302/j.issn.1000-2006.202206004 Abstract （523）   HTML （21）    PDF（pc） （1534KB）（1877）       Knowledge map    Save 【Objective】Environmental and social problems caused by rapid urbanization are increasingly threatening the health of residents, and the optimal allocation of urban park green spaces has become an essential strategy for the built environment of megacities to contribute to mental health positively. This study is to analyze the environmental and health benefits of urban green spaces from the perspective of accessibility, taking into account socio-economic conditions. 【Method】Based on the theoretical analysis of “nature-psychology-society”, an ordered logit and moderating effect model was constructed to explore the impact of urban park green spaces on mental health and to investigate the health inequalities resulting from the moderating effect of socio-economic status. 【Result】The baseline regression results show that improving the accessibility of urban park green spaces can positively influence mental health, and this positive effect tends to decay from the city center to its periphery. The moderating effect analysis revealed that socio-economic status had a positive moderating effect on the relationship between urban park accessibility and the mental health of residents, and significantly strengthened the positive effect of park accessibility on mental health. Heterogeneity analysis revealed that the mental health promotion effect of urban park accessibility was heterogeneous across household registration, gender, and age group and moderated by socioe-conomic status. Urban versus rural, female versus male, and elderly versus youth are more likely to suffer from mental health inequality risks induced by differences in park accessibility. 【Conclusion】To improve the mental health of all urban residents, three aspects should be adopted: optimizing green space layout planning, improving the quality of green space services, and strengthening the management system of green spaces. Table and Figures | Reference | Related Articles | Metrics | Comments（0） Cited:

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Analyzing the genetic diversity of Nymphaea spp. based on SSR markers MAO Liyan, LI Huimin, LONG Lingyun, HUANG Qiuwei, TANG Yuwei, YU Yanping, HUANG Xinyi, TAN Xiaohui, NONG Xiaohui, ZHU Tianlong, LU Zushuang JOURNAL OF NANJING FORESTRY UNIVERSITY    2024, 48 (5): 57-68.   DOI: 10.12302/j.issn.1000-2006.202302029 Abstract （2040）   HTML （84）    PDF（pc） （2779KB）（1874）       Knowledge map    Save 【Objective】Nymphaea spp. (waterlily) are important aquatic flowers. The rapid development of the waterlily industry has led to challenges in identifying genetic backgrounds of newly introduced germplasms in a timely manner due to inadequate introduction management practices. This has resulted in issues such as mislabeling of seedlings and unclear parentage, hampering the effective utilization and innovation of waterlily germplasm resources. This study focuses on developing genome-wide SSR markers for conducting phylogenetic and genetic diversity analyses of waterlily species. These markers are intended to serve as a theoretical foundation for conserving and breeding waterlily germplasm resources.【Method】Based on the published complete genome sequence of waterlily, the SSR loci in 14 chromosome genes were analyzed using the micro satellite identification (MISA) tool. Subsequently, 150 pairs of SSR primers were designed with the assistance of Primer 3.0 software. Five native germplasms were chosen for PCR amplification utilizing the 150 primer pairs. Following PCR, SSR primers demonstrating high polymorphism were identified through agarose and denaturing polyacrylamide gel electrophoresis. The selected SSR primers were synthesized with fluorescent primers (FAM and HEX) before amplifying 147 waterlily samples via PCR. The resulting products were then assessed using capillary electrophoresis, and the raw data were analyzed using GeneMarker software. Fragment sizes at each allele site for every sample were compiled into a 0/1 matrix. Genetic diversity indices, cluster analysis, and principal component analysis were computed using Popgenen and NTSYS software toos.【Result】11 pairs of SSR primers exhibiting distinct bands and high polymorphism were carefully chosen following the analysis of agarose gel and polyacrylamide gel electrophoresis results. These selected primers were employed to evaluate the genetic diversity among 147 waterlilies. Capillary electrophoresis revealed the presence of 307 alleles. The polymorphism index (PIC) ranged from 0.46 to 0.60, average at 0.53. The effective allele number (Ne) rangedfrom 1.042 8 to 1.117 5, with an average of 1.071 8. Nei’s gene diversity index (H) ranged from 0.038 0 to 0.086 2, averaging at 0.056 2. The Shannon diversity information index (I) ranged from 0.085 6 to 0.163 8, averaging at 0.114 4. Cluster analysis indicated genetic similarity coefficients ranging from 0.781 8 to 0.993 5 among the 147 waterlilies, with an average coefficiency of 0.899 2. These waterlilies were classified into six groups based on a genetic similarity coefficient was 0.879 0. Principal coordinates analysis (PCoA) displayed results closely aligned with traditional morphological classification for the 147 waterlilies. The first, second and third principal coordinates accounted for 16.54%, 8.35% and 5.43% of the total genetic variation, respectively, comprising 30.32% altogether. The first coordinate was correlated with aroma formation and stamen development, the second with flowering time and environmental adaptability, and the third with flower types.【Conclusion】11 pairs of SSR primers displaying substantial polymorphism were chosen, demonstrating efficacy in distinguishing the genetic relationships among 147 waterlilies. These waterlilies were systematically categorized into six primary branches, with classification outcomes mirroring traditional morphology categorizations. The selected 11 pairs of SSR primers have potential utility in analyzing genetic diversity and identifying waterlily species. The SSR markers findings stand poised to offer a robust scientific foundation for germplasm collection, preservation, innovation, and the development of waterlily species. Table and Figures | Reference | Related Articles | Metrics | Comments（0） Cited:

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Recent advances in molecular regulatory mechanisms of DNA methylation in plant tissue culture GUO Ying, YANG Ganggui, WU Yuhan, HE Jie, HE Yujie, LIAO Haoran, XUE Liangjiao JOURNAL OF NANJING FORESTRY UNIVERSITY    2023, 47 (6): 1-8.   DOI: 10.12302/j.issn.1000-2006.202302020 Abstract （1052）   HTML （126）    PDF（pc） （6225KB）（1871）       Knowledge map    Save Exerting remarkable cell totipotence, plants are able to regenerate tissues/organs and even individuals from differentiated cells activated by wound stress and/or hormonal cues. Based on the theory of plant cell totipotency, techniques of plant tissue culture have been widely used in rapid propagation, germplasm conservation, and plant breeding as a type of conserved epigenetic modification. However, the understanding of how plant cells retain both differentiated status and developmental plasticity is still obscure, especially at the epigenetic level. DNA methylation is an evolutionarily conserved epigenetic modification that can intricately coordinate cell fate transition and pluripotency establishment during the plant regenerate process. In the work, the recent progress in the regulation of plant regeneration through DNA methylation was summarized, starting from the formation of callus and somatic embryogenesis during tissue culture. Firstly, the change patterns of DNA methylation in different plant regeneration processes were analyzed, showing that both explants type and regeneration phase had an effect on DNA methylation levels. The role of some DNA methyltransferase in plant regeneration was studied, such as DNA Methyltransferase1 (MET1), whose deletion can lead to increased WUS expression and promote shoot regeneration. RNA-directed DNA methylation (RdDM) is the main molecular pathway responsible for de novo DNA methylation in all contexts and is believed to play an important role in plant regeneration. Meanwhile, we analyzed the molecular regulatory mechanisms of DNA methylation on the expression of regenerative genes, such as BBM (baby boom), WOX (wuschel-related homeobox), WIN (wound induced dedifferentiation), etc. Finally, we discussed the future research directions of DNA methylation in the field of plant regeneration. The combination of tissue culture and genetic engineering will provide opportunities for efficient reproduction and precise cultivation of agricultural and forestry crops. Further, the regeneration-related genes reported in this study will provide candidates for plant regeneration research of genetic and molecular mechanisms. Table and Figures | Reference | Supplementary Material | Related Articles | Metrics | Comments（0）

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Xylem anatomical and hydraulic traits of trees with different wood properties in a temperate forest in northeast China ZHANG Rui, ZHOU Zhenghu, WANG Chuankuan, JIN Ying JOURNAL OF NANJING FORESTRY UNIVERSITY    2024, 48 (3): 229-236.   DOI: 10.12302/j.issn.1000-2006.202209061 Abstract （1484）   HTML （30）    PDF（pc） （2684KB）（1843）       Knowledge map    Save 【Objective】 Xylem anatomy affects the water transport efficiency and drought resistance of trees, which in turn affects tree growth and survival. Therefore, studying xylem anatomical and hydraulic traits will enable a better understanding of the response and adaptation mechanisms of trees to environmental changes. 【Method】 Here, we measured xylem anatomical and hydraulic traits in 20 tree species with three different wood properties (11 diffuse-porous, 5 ring-porous, and 4 non-porous) in a temperate forest in northeastern China. Our aim was to examine the differences in stem anatomical and hydraulic traits of tree species with three different wood properties and explore the potential relationships between stem hydraulic and anatomical traits. 【Result】 We found that there were significant differences in the anatomical traits (mean vessel (tracheid) diameter, maximum vessel (tracheid) diameter, vessel (tracheid) density, mean vessel (tracheid) area, proportion of lumen area), and hydraulic traits (theoretical hydraulic conductivity, hydraulic diameter, vessel (tracheid) mechanical strength, Huber value) among the tree species with different woody properties (P<0.05). The ring-porous trees had the highest theoretical hydraulic conductivity, whereas the non-porous trees had the highest tracheid mechanical strength. Theoretical hydraulic conductivity was significantly correlated with all anatomical traits. Huber values (sapwood area/leaf area) were significantly correlated with all anatomical traits (P<0.05), except vessel (tracheid) wall thickness and maximum vessel length. However, there were no significant correlations between wood density and all anatomical traits (except vessel length). 【Conclusion】 We concluded that wood density cannot better reflect the hydraulic traits of trees in temperate forests in northeastern China and that their water transport capacity is dependent on the xylem anatomical structure and the balance between a tree’s supply and demand for water. Table and Figures | Reference | Related Articles | Metrics | Comments（0）

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A novel approach for leaf area retrieval from terrestrial laser scanned points LI Shuangxian, LU Xin, Duojie Cairen, ZHANG Huaiqing, XUE Lianfeng, YUN Ting JOURNAL OF NANJING FORESTRY UNIVERSITY    2023, 47 (5): 28-38.   DOI: 10.12302/j.issn.1000-2006.202210012 Abstract （897）   HTML （24）    PDF（pc） （3649KB）（1826）       Knowledge map    Save 【Objective】Terrestrial laser scanning involves collecting dense laser point clouds of plants to finely characterize the structural parameters of a forest, such as tree skeletons and true leaf area. True leaf area is an important index for phenotypic studies in forestry and botany. At present, there are no well-evidenced methods for measuring phenotypic traits in plant science. Here we develop a novel approach for true leaf area retrieval from terrestrial laser scanned points to appraise key phenotypic parameters. 【Method】 First we designed an individual leaf segmentation algorithm based on the small plane locating and region growing for plant point clouds, to achieve an accurate single-leaf point cloud segmentation. Second, we input three parameters: the angle between the normal vector of a single leaf and the incident laser beam from the scanner, the distance between the scanner and leaf, and the number of point clouds of a single leaf. Training samples combined L1 and L2 regularized multiple regression methods to realize inverse calculations of the total leaf area of all leaf elements in a tree canopy. Finally, we chose four individual trees on our campus(crape myrtle, cherry, ginkgo and camphor) to verify the effectiveness of our results by comparison with field measurements. 【Result】Leaf area retrieval results indicated the superiority of our approach over existing least-square fitting methods. Compared with field measurements, we saw better performance for two small trees: the crape myrtle [coefficient of determination (R2) was 0.95 and root mean square error (RMSE) was 0.42 cm2] and the cherry (R2 = 0.9 and RMSE was 0.42 cm2). Appreciable results were achieved for the ginkgo (R2 = 0.83 and RMSE was 1.24 cm2) and camphor trees (R2 = 0.86; RMSE was 1.10 cm2); these are larger trees with extended crowns and more vegetative elements in the canopy. 【Conclusion】 This method synergistically employed a computer vision and machine learning to accurately calculate the leaf area of canopies using scanned points, yielding novel perspectives for assessing the true leaf area of canopies. Table and Figures | Reference | Related Articles | Metrics | Comments（0） Cited:

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New management model of construction techniques, realistic genetic gain and low cost multi-generation improvement in seedling seed orchard of Pinus massoniana WANG Zhangrong, JI Kongshu, XU Li’an, ZOU Bingzhang, LIN Nengqing, LIN Jingquan JOURNAL OF NANJING FORESTRY UNIVERSITY    2023, 47 (6): 9-16.   DOI: 10.12302/j.issn.1000-2006.202210025 Abstract （1452）   HTML （48）    PDF（pc） （1803KB）（1814）       Knowledge map    Save 【Objective】This manuscript described the realized genetic gain and construction techniques of an open-pollinated seedling and seed orchard of Masson pine (Pinus massoniana). 【Method】The orchard was established in the 1990 to 1992 period and covers an area of 33.33 hm2 in Baisha State-Owned Forest Farm, Shanghang County, Fujian Province, China. The orchard comprises more than 198 families of trees that were intensively selected from the excellent provenance area of Fujian Province. The orchard design was classified into two types: (1) Combined design of seed production area with progeny test area. (2) Separated design of seed production area and progeny test area. Based on the results of open-pollinated forests progeny test, trees with the lower breeding values were removed from the seed orchard (genetic thinning) on three occasions in 2000, 2004 and 2008, respectively. In 2003, a progeny test forest with seedlings from 68 half-sib families of the seedling seed orchard including a commercial check was established.【Result】A realistic genetic gain of 8.5% was obtained based on a test of 6-year offspring of Masson pine open-pollinated seedling seed orchard, and the volume growth of improved seed plantation was increased by 30% more than that of the unimproved stand. The results of simple sequence repeat (SSR) molecular analysis showed that the seedling seed orchards had high genetic diversity and random mating degree. The establishment of the first generation free-pollinated seed garden of Masson pine was successful. The following are the two key findings: (1) Quality and quantity of superior tree selection is the basis for achieving high genetic gain and continuing genetic improvement. (2) Scientific genetic evaluation of the progeny population and genetic thinning in the production population are the key techniques. (3) The detection, regulation and daily management of the mating system in a seed orchard are important conditions to ensure the normal operation of the orchand. 【Conclusion】 (1) For some fast-growing tree species such as eucalyptus and Masson pine, the seed orchard crops are not appropriate for pruning and dwarfing culture. It is more advantageous to adopt the technique of “Integrating the measured population and the producing population” to build the orchard. (2) Information regarding juvenile-adult correlation of the main traits of the established tree species is not yet available. It is necessary to carry out pruning and dwarfing culture. It is valuable to use the separated design of seed production area and progeny test area and to use the genetic evaluation data obtained from the separated progeny test to guide the genetic thinning of production population in the seed orchard production. In a word, the multi-generation seed orchard should be established in a location with good isolation conditions and relatively gentle terrain, and the orchard crops should be maintained without pruning and dwarfing to retain the natural tree shape. After completion of the production task in the seed orchards, the seed orchard trees could be transformed into forest tourism forest, forest health forest or timber reserve forest, to give full play to the multiple functions of the forest and reduce the operating cost of the forest improved seed base. This is a new model of multi-generation low-cost construction of seed orchards worth exploring. Table and Figures | Reference | Related Articles | Metrics | Comments（0） Cited:

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Conservation status and prioritization of rare and endangered plants in Jiangxi Wuyishan National Nature Reserve CHEN Lin, CAO Xiaomeng, PAN Tingting, LEI Ping, ZENG Lijian, LI Meng, YI Xiangui JOURNAL OF NANJING FORESTRY UNIVERSITY    2024, 48 (5): 39-47.   DOI: 10.12302/j.issn.1000-2006.202212017 Abstract （2350）   HTML （98）    PDF（pc） （1499KB）（1799）       Knowledge map    Save 【Objective】This research aims to determine the actual threat level and prioritize the conservation of rare and endangered plants in the Wuyishan National Nature Reserve in Jiangxi Province, provide a reference for the conservation of these plants in the nature reserve.【Method】Using the line transect method combined with historical literature, the endangered coefficient, genetic value coefficient, and species value coefficient were used to quantitatively analyze the conservation priorities of 113 rare and endangered wild plants in the Wuyishan National Nature Reserve in Jiangxi Province. The relationship between the rare and endangered plants of Wuyishan in Jiangxi Province and five adjacent areas, namely Wuyishan in Fujian Province, Tianmushan in Zhejiang Province, Lushan in Jiangxi Province, Wanchaoshan in Hubei Province, and Jinfoshan in Chongqing City, were compared using the Sorensen similarity coefficient.【Result】(1) There were 113 species of rare and endangered plants in the reserve, belonging to 47 families and 85 genera. Among these, there were 6 species classified as National Class Ⅰ, 15 species as National Class Ⅱ. 20 species were classified as Jiangxi Province Class Ⅰ, 11 species as Jiangxi Province Class Ⅱ, 55 species as Jiangxi Province Class Ⅲ, and 12 species endemic to Jiangxi. (2) According to the quantitative analysis of conservation priority, 17 species (15.04%) were assessed as first class, 41 species (36.28%) as second class, 54 species (47.79%) as third class, and 1 species (0.89%) as fourth class. (3) The similarity coefficient between Wuyishan in Jiangxi Province and the five adjacent areas were about 30%. However, Wuyishan in Jiangxi Province owned more rare and endangered plants (38 species) and a higher proportion of species per unit area (0.24), indicated a higher conservation value.【Conclusion】 The excellent habitats and abundant rare and endangered plants in Wuyishan in Jiangxi Province indicate a high conservation value. The assessment and classification of the 113 rare and endangered plants more accurately reflect their current situation in the Nature Reserve, providing a reference for effective conservation plans for threatened species. Table and Figures | Reference | Related Articles | Metrics | Comments（0） Cited:

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Cloning of the Liriodendron chinense LcPIN1a genes and its effect on plant growth and development HAO Zhaodong, MA Xiaoxiao, WANG Dandan, LU Ye, SHI Jisen, CHEN Jinhui JOURNAL OF NANJING FORESTRY UNIVERSITY    2024, 48 (6): 51-61.   DOI: 10.12302/j.issn.1000-2006.202404005 Abstract （864）   HTML （48）    PDF（pc） （5246KB）（1797）       Knowledge map    Save 【Objective】This study aimed to explore the role of the auxin transporter PIN1 in plant growth and development in Liriodendron chinense.【Method】Three PIN1 homologous proteins were identified in the Liriodendron genome using bioinformatic methods, and expression pattern analyses of the three LcPIN1s genes were performed in different tissues and response to various abiotic stresses. An overexpression vector driven by the CaMV35S promoter was then constructed and transformed into Arabidopsis and Liriodendron×sinoamericanum, followed by phenotypic determination of growth and developmental traits in the transgenic positive lines.【Result】Three PIN1 homologous proteins were identified in the Liriodendron genome, named LcPIN1a, LcPIN1b and LcPIN1c. Expression pattern analyses showed that LcPIN1a was mainly expressed in leaves, while LcPIN1b and LcPIN1c were primarily expressed in roots and stems and stigmas when the plantlets transitioned into reproductive growth. In addition, all three LcPIN1 genes transcriptionally responded to drought stress, with LcPIN1b and LcPIN1c showing dependence on the biosynthesis of endogenous ABA, while LcPIN1a does not. Root length and plant height were significantly reduced in LcPIN1a-heterologous overexpression (LcPIN1a-HO) lines compared to wild-type Arabidopsis. The number of stamens was predominantly five in LcPIN1a-HO lines, whereas wild-type Arabidopsis typically contained six stamens. The regeneration of plantlets in LcPIN1a-overexpressing (LcPIN1a-OE) Liriodendron×sinoamericanum was significantly reduced compared to wild-type plants. In addition, the root length and plant height of LcPIN1a-OE regenerated seedlings were significantly lower than those of the wild type. The root structure of LcPIN1a-OE plants was significantly changed, with the taproot being less distinct.【Conclusion】The PIN1 proteins of L. chinense play a crucial role in vegetative and reproductive growth. Overexpression of LcPIN1 genes can be detrimental to normal plant growth and development. Table and Figures | Reference | Related Articles | Metrics | Comments（0） Cited:

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Community assembly mechanism for different planting ages of Chinese fir artificial forests in subtropical China LU Xudong, DONG Yuran, LI Yao, MAO Lingfeng JOURNAL OF NANJING FORESTRY UNIVERSITY    2024, 48 (1): 67-73.   DOI: 10.12302/j.issn.1000-2006.202212037 Abstract （2656）   HTML （38）    PDF（pc） （2727KB）（1768）       Knowledge map    Save 【Objective】 The process of community establishment in Chinese fir (Cunninghamia lanceolata) artificial forest, as one of the most significant ecosystems and sources of timber in China’s subtropical regions, is crucial for understanding the coexistence of species and the maintenance of biodiversity in plantation forests. The objective of this study is to investigate the process of community assembly and underlying mechanisms of Chinese fir artificial forests in Chinese subtropical, and provide a theoretical basis for enhancing the stability of local biodiversity in the management of Chinese fir artificial forests. 【Method】 Data from 143 pure Chinese fir artificial forests with a wide age range (3-100 years old) in subtropical China were collected through literature search and field sampling surveys. The changes in community phylogenetic structure with forest age and breast height diameter were examined to explore the variations in environmental filtration, competitive exclusion, and stochastic processes during stand development. 【Result】 Overall, as the forest age increased, the net relatedness index (NRI) and net taxon index (NTI) of plant communities in Chinese fir artificial forests initially decreased and then leveled off. The phylogenetic structure transitioned from aggregation to stochastic processes and eventually tended to diverge. The changes in NRI were more significant than those in NTI. In the early stage of young stands, NRI and NTI were both higher than 0, indicating aggregation in the phylogenetic structure. Before stand maturity, NRI was lower than 0, and NTI was higher than 0, showing divergence at the community level and aggregation at the end of the evolutionary tree. After stand maturity, both NRI and NTI were lower than 0, indicating a divergent phylogenetic structure. The trend of phylogenetic structure with diameter at breast height (DBH) was consistent with stand age. 【Conclusion】 The community assembly of Chinese fir artificial forests is primarily driven by environmental filtration, followed by a period of stochastic processes, and ultimately dominated by inter-biotic interactions as the forest stand grows and develops. Implementing appropriate forest management measures for different stand ages is beneficial for the coexistence of local species and the maintenance of plant diversity in Chinese fir artificial forests. Table and Figures | Reference | Related Articles | Metrics | Comments（0） Cited:

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Systematic classification of gymnosperms: past, present and future YANG Yong JOURNAL OF NANJING FORESTRY UNIVERSITY    2024, 48 (3): 14-26.   DOI: 10.12302/j.issn.1000-2006.202301020 Abstract （4501）   HTML （323）    PDF（pc） （1706KB）（1715）       Knowledge map    Save The botanical history of gymnosperm classification was reviewed and dividied into six major phases since the initiation of modern taxonomy in 1753 according to landmark concepts or creative classifications. The first phase lasted from Linnaeus to Brown during which the concept of gymnosperm was not conceived, and gymnosperms were not treated as a taxon. This phase was represented by the sexual system of Linnaeus. The second phase was from Brown to Brongniart. In this phase, the concept of gymnosperms was proposed and gradually accepted by botanists at that time, and Brongniart treated gymnosperms as a group in his classification system though the linear sequence, family delineation and relationships among taxa were ambiguous. The third phase was from Brongniart to Braun. In this phase, the gymnosperms were treated as a group within dicotyledons, the classification of Bentham & Hooker was considered as the representative classification systems. The fourth phase was from Braun to Pilger. During this period, the gymnosperms were treated as a separate taxon from angiosperms, the spermatozoids of cycads and ginkgo were discovered, the main lineages of gymnosperms became established, but the family delineation remains ambiguous, representative systems include Eichler and Engler. The fifth phase was from Pilger to Christenhusz et al.. Numerous classifications of gymnosperms were proposed in this phase, various categories were applied to lineages of gymnosperms, different lines of evidence were obtained and utilized including morphology, anatomy, embryology, phytochemistry, palaeobotany, cladistics, the focuses of debates were mainly on the relationships and systematic positions of ginkgo, taxads, and gnetophytes, and the taxonomic delineation of Podocarpaceae, Taxodiaceae and Cupressaceae, the classification systems of Pilger and Wanchun Cheng were representative in this phase. The sixth phase was from Anderson et al. till now. In this phase, people accepted the principles of cladistics, and conducted phylogenetic studies using DNA sequences, and also integrated different lines of evidences in taxonomy. The new classification of gymnosperms proposed by Yang et al. was introduced and the features of this new classification was discussed. Future studies should focus on species delimitation based on Genomic barcoding, integrative taxonomy, and conservation biology. Table and Figures | Reference | Related Articles | Metrics | Comments（0）

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The effects of intercropping of Carya illinoinensis and Camellia sinensis ‘Anjibaicha’ on photosynthetic characteristics of C. sinensis tree during rapid growth period TIAN Mengyang, ZHU Shulin, DOU Quanqin, JI Yanhong JOURNAL OF NANJING FORESTRY UNIVERSITY    2024, 48 (2): 86-96.   DOI: 10.12302/j.issn.1000-2006.202208022 Abstract （3234）   HTML （202）    PDF（pc） （3031KB）（1713）       Knowledge map    Save 【Objective】 This article explores the differences in photosynthetic and fluorescence characteristics of Camellia sinensis ‘Anjibaicha’ at different measuring points of Carya illinoinensis-Camellia sinensis intercropping to provide a theoretical basis for high-efficiency compound cultivation of Carya illinoinensis-Camellia sinensis ‘Anjibaicha’.【Method】 In this compound model, the daily change in photosynthetic rate, light-response curves, fluorescence parameters and chlorophyll content of 10-year-old Camellia sinensis ‘Anjibaicha’ trees were measured in the fast-growing period (July-September) at four measuring points, i.e., under-crown (T1), crown-margin (T2), outside-crown (T3), and single Camellia sinensis comparison (T0).【Result】 The net photosynthetic rate(Pn) of Camellia sinensis ‘Anjibaicha’ could be significantly altered in T2. The Pn values at T1, T2 and T3 were significantly higher than those at T0 in July under high temperatures. The leaves had a midday depression of photosynthesis at T0 in August, and the Pn at T2 was significantly higher than that at T0. The Pn at different measuring points (T1, T2 and T3) were significantly higher than those of T0 in September. Compared with the control (T0), the higher apparent quantum efficiency (ηAQY), maximum net photosynthetic rate ( {P_{\mathrm{n}}}_{,\mathrm{m}\mathrm{a}\mathrm{x}}), and light saturation point (PLSP) were high, and the light compensation point (PLCP) was low at T2. The dark respiration rate (Rd) gradually decreased with decreasing light intensity. From July to September, the chlorophyll content of Camellia sinensis leaves was significantly higher in intercropping than in single Camellia sinensis cropping. With the decrease in light intensity, chlorophyll a (Chla), chlorophyll b (Chlb), and total chlorophyll (Chl) gradually increased, and the chlorophyll a/b value showed a decreasing trend. Camellia sinensis leaves produce more chlorophyll, which helps Camellia sinensis trees capture more light energy for photosynthesis. The maximum photochemical efficiency (FV/Fm) and potential photochemical activity (FV/F0) of PSⅡ of Camellia sinensis trees in intercropping were significantly higher than those of single Camellia sinensis cropping in July and August. The light energy conversion efficiency and electron transfer ability of Camellia sinensis ‘Anjibaicha’ leaves in single cropping decreased because high temperature and high-intensity light could produce obvious photoinhibition. In September, the FV/Fm and FV/F0 of Camellia sinensis trees at T2 during intercropping were significantly higher than those of T1 and T0. The results showed that excessive shading inhibited the photochemical activity of PSⅡ, which blocked energy transfer and transformation in photosynthesis. 【Conclusion】 In the Carya illinoinensis-Camellia sinensis ‘Anjibaicha’ forest compound model, many photosynthetic physiological indexes of Camellia sinensis ‘Anjibaicha’ were improved, among which the crown-margin (T2) environment was favorable for the photosynthesis of Camellia sinensis ‘Anjibaicha’ leaves, followed by the outside-crown (T3), and the under-crown (T1) and monoculture (T0) were poor. High temperature and high-intensity light have obvious photoinhibition in single-cropped Camellia sinensis ‘Anjibaicha’, which reduced photosynthetic efficiency. Table and Figures | Reference | Supplementary Material | Related Articles | Metrics | Comments（0） Cited:

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Screening and analysis of differential secondary metabolites in Castanea mollissima with different levels of resistance to Oligonychus ununguis ZHANG Xinfang, WANG Guangpeng, ZHANG Shuhang, LI Ying, GUO Yan JOURNAL OF NANJING FORESTRY UNIVERSITY    2024, 48 (2): 234-240.   DOI: 10.12302/j.issn.1000-2006.202209053 Abstract （4588）   HTML （167）    PDF（pc） （1947KB）（1708）       Knowledge map    Save 【Objective】 The differential secondary metabolites in chestnut (Castanea mollissima) leaves with different mite resistance levels were screened to provide a reference for the analysis of the mite(Oligonychus ununguis) resistance mechanism and the breeding of highly mite-resistant chestnut varieties.【Method】 The chestnut varieties ‘Yanxing’ and ‘Likang’ were used to identify and determine the mite resistance levels to O. ununguis with the field investigation method. Metabolomics detection was performed using ultra-high-performance liquid chromatography and tandem mass spectrometry, and the differential metabolites were screened using a combination of fold change and the variable importance in projection value. The R software (ComplexHeatmap and MetaboAnalystR package) was used to draw the clustering heat map and orthogonal partial least squares-discriminant analysis score map. Identified metabolites were annotated using the Kyoto encyclopedia of genes and genomes (KEGG) database, and the annotation results were classified by pathway types.【Result】 The resistance levels of ‘Likang’ and ‘Yanxing’ to O. ununguis were high resistance and susceptible, respectively. A total of 704 secondary metabolites were detected, including 165 differential metabolites. The content of 73 metabolites in ‘Likang’ was significantly higher than in ‘Yanxing’, and the content of 92 metabolites was lower in ‘Likang’ than in ‘Yanxing’. The types of differential metabolites included 56 phenolic acids, 60 flavonoids, 19 lignins and coumarins, four tannins, five alkaloids, 16 terpenoids and five other types. Flavonoids and phenolic acids accounted for 36% and 34%, respectively. Metabolites present only in ‘Likang’ included caffeoylcholine-4-O-glucoside, 3-hydroxy-5-methylphenol-1-O-(6'-galloyl)glucoside, tricin-7-O-glucuronide, 6'-trans-cinnamoyl-8-epikingisidic acid, lariciresinol-4'-O-glucoside, albanol B and sanguiin H11. There were 15 metabolites present only in ‘Yanxing’, including 4-methyl-5-thiazoleethanol, 2,4-dihydroxybenzoic acid, isofraxidin, salicin and roxburic acid. Thirty-three differential metabolites in ‘Yanxing’ and ‘Likang’ were annotated to 12 metabolic pathways.【Conclusion】 The secondary metabolic profiles between the mite-susceptible variety ‘Yanxing’ and the highly resistant variety ‘Likang’ differed. Secondary metabolites that may be related to chestnut mite resistance were prunetin, epigallocatechin, caffeic acid, ferulic acid, several lignans and 4-methyl-5-thiazoleethanol. The differential secondary metabolites were mainly annotated and enriched in the flavonoid biosynthesis pathway and the flavone and flavonol biosynthesis pathway. Table and Figures | Reference | Related Articles | Metrics | Comments（0）

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Studies on the phenotypic traits and quality characteristics of seven superior tree nuts of Torreya grandis ‘Merrillii’ TAO Tao, LIU Yaohui, XUE Zhongjun, GAO Yue, YUAN Luhong, ZHENG Fen, WU Wei, HUANG Jieying JOURNAL OF NANJING FORESTRY UNIVERSITY    2024, 48 (2): 37-44.   DOI: 10.12302/j.issn.1000-2006.202211034 Abstract （4120）   HTML （251）    PDF（pc） （1523KB）（1670）       Knowledge map    Save 【Objective】 This study investigated seven nuts of Torreya grandis‘Merrillii’ to compare and analyze the primary physical properties and content of the main components, understand the quality of T. grandis in Yi County, and provide a theoretical basis for the selection, development, and utilization of improved varieties of T. grandis ‘Merrillii’【Method】 Seven T. grandis were selected ‘Merrillii’ germplasms from Yi County, southern Anhui Province; measured their phenotypic characteristics, mineral elements, nutrient composition, fatty acid composition, and 29 additional physical and chemical properties; and carried out correlation and cluster analyses on the measured data. 【Result】 The phenotypic characteristics and internal quality indices of T. grandis ‘Merrillii’ differed significantly (P < 0.05). The crude protein content ranged from 6.67% to 14.69%. The crude fat content varied from 36.20% to 55.51%, among which the highest average content of polyunsaturated fatty acids was linoleic acid at 47.81%, followed by chrysotile acid at 12.20%. The total potassium (TK) content varied from 0.77% to 1.39%, and there was a significant difference between different superior plants (P < 0.05). 【Conclusion】 According to the comprehensive analysis, the crude protein content of the oblong-shaped Zhujiyihao and Zhejiangxifei was higher than that of T. grandis ‘Merrillii’ types with a round appearance, while the oil acid value of the oblong T. grandis ‘Merrillii’ kernel was lower, and the oil quality was better. Acid value, nuclear shape index, and oleic acid content can be used as the optimum indexes for screening superior plants of T. grandis ‘Merrillii’. Table and Figures | Reference | Related Articles | Metrics | Comments（0） Cited:

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Research progress and prospects of biological basis in Magnolia biondii YIN Zengfang, OU Xiang, CHEN Yao, YANG Aixiang, SUN Liyong JOURNAL OF NANJING FORESTRY UNIVERSITY    2024, 48 (2): 256-262.   DOI: 10.12302/j.issn.1000-2006.202307006 Abstract （4394）   HTML （174）    PDF（pc） （2053KB）（1548）       Knowledge map    Save Magnolia biondii is an economically important tree in China, serving various medicinal, material and ornamental purposes. The species has extensive use in landscaping and practical applications. Despite numerous studies focusing on the growth and breeding characteristics of M. biondii, there remains a lack of a systematic summary of the results from basic biological research. This paper comprehensively reviews research advancements in various aspects of M. biondii, including individual growth and development characteristics, rapid propagative techniques, germplasm resource selection, genomics overview and other research areas. We present essential findings from basic biological research and discuss future research directions. Emphasis is given to furthering research efforts in breeding techniques, innovating germplasm resources, screening for quality and functional traits, and elucidating regulatory mechanisms. This will establish a scientific foundation for studying on development and application of M. biondii germplasm resource, and for understanding the growth regulation mechanisms within Magnoliaceae. Table and Figures | Reference | Supplementary Material | Related Articles | Metrics | Comments（0） Cited:

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Exploration of dynamic changes of sound diversity based on acoustic index in the Shennongjia National Park, China LUO Li, HOU Yanan, YANG Jingyuan, YU Xinwen, GAO Lingwang, OUYANG Xuan, YANG Minglun, GAO Jiajun, GUO Anqi, LIU Yukun JOURNAL OF NANJING FORESTRY UNIVERSITY    2023, 47 (5): 39-48.   DOI: 10.12302/j.issn.1000-2006.202208003 Abstract （979）   HTML （17）    PDF（pc） （4214KB）（1502）       Knowledge map    Save 【Objective】The study aims to evaluate the response of acoustic indices to the dynamic changes of animal sound diversity, further to explore the characteristics of the variation of animal sound diversity in Shennongjia National Park, China, in order to provide a quantitative basis for the local ecological protection. 【Method】We deployed nine sound recording equipments in nine sampling sites in Shennongjia National Park, and sound recording data from May to July 2021 were obtained. A time series of eco-acosutic indices including acoustic complexity index (ACI), bioacoustic index (BI), normalized difference soundscape index (NDSI) were extracted from the recording data after noise reduction processing. Further the summer dynamic characteristics of these three acoustic diversity indices were analyzed.【Result】Results showed that the variation of ACI was not obvious during the recording period, while BI showed a double peak variation, NDSI index showed a triple or four peak variation. Results of the Mann-Kendall mutagenicity test showed that ACI only had a mutations at a few sampling sites, while BI and NDSI had mutation at most of the sampling sites. And the analysis of daily variations on the date of the index mutation suggested that weather and human disturbance are the main causes of the index mutation. Results of daily changes of acoustic indices showed that the variation of ACI was not obvious also, while BI and NDSI had a obvious diurnal variation trend, which was consistent with the species of dawn/dusk chorus. The spatial variation of acoustic indexes with altitude gradient indicated that ACI and BI have the maximum value in the middle altitude area, and ACI has a strong correlation with the altitude, while the NDSI has no obvious change.【Conclusion】Our results demonstrated that BI and NDSI could better reflect the dynamic changes of animal sound diversity over time, and the changes of animal sound diversity in Shennongjia National Park showed a multi-peak variation during the recording period, and weather and human activities would cause the abrupt change. The ACI can well explain the spatial variation of animal sound diversity, and the maximum diversity was found in the middle altitude area. Table and Figures | Reference | Supplementary Material | Related Articles | Metrics | Comments（0）

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Alkali stress tolerance analysis of four Rhododendron cultivars GONG Rui, XIA Xi, ZHANG Chunying JOURNAL OF NANJING FORESTRY UNIVERSITY    2024, 48 (2): 113-120.   DOI: 10.12302/j.issn.1000-2006.202207014 Abstract （3298）   HTML （177）    PDF（pc） （2942KB）（1487）       Knowledge map    Save 【Objective】 This study aims to analyze the tolerance differences of Rhododendron cultivars to alkali stress and effects on accumulation and distribution of mineral elements in different organs of rhododendron, and investigate the response mechanism of rhododendron to alkali stress. The results of this study provide a theoretical basis for breeding alkali-tolerant varieties. 【Method】 Alkaline salt solution Na2CO3-NaHCO3 (volumn fraction 1∶9) was used to adjust the pH value of deionized water to 7.52 and 9.14, respectively. Four Rhododendron cultivars (Rhododendron ‘Zihe’, R. ‘Kirin’, R. ‘Yanzhi Mi’ and R. ‘Fenxiu’) were treated with pot watering of alkaline solution for two months, and the growth of plants, as well as physiological and biochemical indexes such as chlorophyll content, root vigor, ferric reductase activity and mineral content were measured. 【Result】 The different varieties of Rhododendron were significantly different in terms of their tolerance to alkali stress. Those plants with weak resistance showed symptoms of alkali damage, such as the yellowing of leaves or leaves drying and falling off, root blackening and even death. With an increase in alkaline stress, the high increment and dry matter ratio of the different varieties decreased significantly. The analysis of plant dry matter quality showed that the dry matter quality of the underground part of R. ‘Kirin’ and R. ‘Yanzhi Mi’ decreased significantly with the increasing degree of alkali stress; R. ‘Zihe’ significantly decreased under high alkali stress, and R. ‘Fenxiu’ had no significant difference among different treatments. The chlorophyll content and root activity of rhododendron decreased significantly, and root iron reductase activity increased. The root activity of R. ‘Zihe’ and R. ‘Fenxiu’ showed no significantly difference under different alkali intensities, while the root activity of R. ‘Kirin’ and R. ‘Yanzhi Mi’ significantly decreased compared with the control. Only R. ‘Zihe’ showed significantly higher root iron reductase activity than the control under high alkali stress, whereas the other three cultivars showed no significantly difference among different treatments. An increase in alkali stress affected the accumulation and distribution of different mineral elements in the rhododendron. Na and Fe ions content significantly accumulated in the root system, whereas K+ and Ca2+ were concentrated in the leaves, and the content decreased significantly. The content of Na+ in the leaves varied among cultivars. After alkali stress treatment, the content of Na+ in leaves of R. ‘Yanzhi Mi’ and R. ‘Kirin’ increased significantly, but there was no significant change in R. ‘Zihe’ and R. ‘Fenxiu. ’ 【Conclusion】 Based on the above indexes, R. ‘Zihe’ and R. ‘Fenxiu’ had strong alkali resistance, followed by R. ‘Yanzhi Mi’, and the alkali resistance of R. ‘Kirin’ was weak. Table and Figures | Reference | Supplementary Material | Related Articles | Metrics | Comments（0）