【Objective】To improve the ecological, social and economic functions of urban river landscapes, qualitative and quantitative evaluations were combined to construct an evaluation model of water-sensitive river landscapes, and clarify the key direction of subsequent design of river landscape. 【Method】Taking Nanjing Crescent Lake as the research object, an urban water-sensitive river landscape evaluation system was constructed using the Analytic Hierarchy Process (AHP). Diversity, richness of waterscape levels, personalized landscape, artistic rainwater treatment, environmental coordination, public participation, ecological education, management and maintenance, flood control and water storage were used as indicators, and the weight of each indicator layer was determined according to expert opinions and combined with different backgrounds. The data of the population questionnaire survey was used to evaluate the suitability of each index of Crescent Lake by the distance index method.【Result】The data showed that the index of water-sensitivity landscape distance of Crescent Lake is 0.36, the evaluation level is basically suitable, the ecological distance index is 0.48 (basically suitable). the aesthetic distance index is 0.26 (basically suitable), and the functional distance index is 0.19 (suitable). The weight of the factors showed that Crescent Lake still needs to realize the purification, collection, storage and utilization of rainwater resources, as well as the artistic design of rainwater facilities and landscapes, increase the type and area of biological habitats, increase the types and numbers of water-sensitive plants, and restore the ecological environment. Through the data analysis of the evaluation of people with different backgrounds, we concluded that there are significant differences in the evaluation results in indicators such as biological habitat diversity, plant species diversity, waterscape layer richness, artistic rainwater treatment, ecological education, and management and maintenance. 【Conclusion】The water-sensitive river landscape evaluation model constructed in this study can provide a theoretical basis for the subsequent evaluation and design of urban river landscapes, and clarify the design direction for the subsequent sustainable development of river landscapes.
Elite cultivars provide important foundations for enhancing carbon sink capacity and increasing the productivity of forest plantations. Forestry germplasm resources breeding and quality improvement has been one of the national key research and development programs during the 14th Five-Year Plan period in China. For ensuring timber safety and achieving dual-carbon goals, it is strategically important to break through the bottleneck that restricts the increase in breeding efficiency and the genetic gain of forest trees. Due to the long period, low efficiency, and low phenotypic selection accuracy of traditional breeding approaches, modern breeding technologies represented by molecular breeding have become a critical path towards high-efficient genetic improvement of forest trees. This is because it can considerably shorten breeding cycles and improve target traits with precision. This paper analyzed the main problems limiting the genetic improvement of forest trees, reviewed the key and core technologies for accelerating the tree breeding process, such as genomic selection breeding, and further discussed some future perspectives for this area. This review will provide useful information for accelerating the revolution and innovation of genetic improvement in forest trees.
The genetic improvement of Masson pine (Pinus massoniana) in China started in the 1950s, comprehensively developed in the late 1970s and early 1980s, and rapidly advanced with the integration of post-modern biotechnology in the new century. In this review, we comprehensively summarized the research work (including provenance trials, superior tree selection, establishment of seed production stand and seed orchard, clone selection, wood properties improvement, and modern biotechnology-assisted breeding), major achievements, innovation, and leading role and contribution to society of the Nanjing Forestry University Group on Masson pine over the past 60 years. Additionally, the improvement experience is summarized. Facing new opportunities and challenges, and in view of the characteristics of the species, existing research basis and social needs, and development trend in the field of biology, we suggest that the genetic improvement of Masson pine in the future should be based on the work of germplasm resources, multi-objective selection and breeding, family and clone forestry needs, and integration of conventional and modern biotechnology. More attention should be given to the breeding fields of pine wood nematode-resistant, pulp making, and high-yield turpentine varieties, and basic and advanced research and its integration into conventional breeding. The above research will be beneficial to the genetic improvement of this tree species.
The theory and technology of “Non-timber Forest-based Economics” are developed in the bachround of to deepening of the international community’s understanding of the key role of forests in the global sustainable development, especially the multi-functional role of forests, the protection of biodiversity, the maintenance of water and land resources, and the provision of a variety of wood and non-wood forest products, as well as the development of forest ecological economy, the promotion of sustainable forest management and the deepening of multi-functional forest construction.It conforms to the trend of the development of forest-related interdisciplinary frontiers in the world.“Non-timber Forest-based Economics”, focuses on the complete and modern concept of forest resources, takes the forest eco-economic system as the research object, takes the output of non-timber forest products and forest ecological products as the goal, and takes multi-disciplinary integration theory and technology as the means to systematically study the characteristics and functions of underforest economic resources, together with the basic theory, basic methods and scientific and technological system formed by its ecological protection, cultivation, management and development and scientific and rational utilization. Research on the basic theory of “Non-timber Forest-based Economics”, comes from Ecology, Economics, Ecological Economics, Agriculture (Forestry) and other disciplines, and the main body is composed of under-forest economic resources, under-forest ecology, agroforestry management, under-forest economic industry management and so on.Based on the natural solutions and natural benefit-oriented economic growth, “Non-timber Forest-based Economics” in the future will focus on the protection, cultivation and intensive processing and utilization of undergrowth economic biological resources, the construction of structural optimization, functional coordination, healthy and stable forest ecosystem supply services, the optimization and adjustment of agroforestry complex system and the promotion of benefits. Efforts should be made to establish an industrial system with high efficiency, high yield, high quality and sustainability.This paper analyzes the background of the development of under-forest economics, summarizes the development status of under-forest economy, expounds the discipline connotation, characteristics, research object and discipline system focus of under-forest economics, and looks forward to the focus and breakthrough direction of underforest economy research.
Wheel wingnut (Cyclocarya paliurus), the sole species in its genus, is a well-known multi-function tree species and has an enormous development potential. The study of C. paliurus began in the late 1970s, whereas the development of C. paliurus industry has been greatly promoted in China since its leaves have been approved as the new food raw materials by National Health and Family Planning Commission of China in 2013. Based on the description of natural distribution and potential suitable cultivation areas of C. paliurus, the research context and the development process of C. paliurus industry were discussed from the perspectives of the relevant paper publication, patent applications and social attention. However, more attentions were paid to the research progress on the silviculture of C. paliurus leaf resources in this paper, such as research progress in the collection and evaluation of germplasm resources and its population genetic diversity, genomics and metabolic regulation of bioactive substances, geographical variation of bioactive substances in its leaves, and theory and technology of oriented cultivation of its leaf plantations. Meanwhile, main problems during the development of C. paliurus industry were also briefly discussed in the paper, and some suggestions were proposed in order to promote the healthy and sustainable development of the C. paliurus industry. These suggestions included: strengthening the creation and clonalization of the superior varieties, optimizing orientation cultivation patterns and its GAP cultivation, reinforcing the study on the extraction and function of active substances, and attaching importance to the development and industrialization of high value-added products of C. paliurus.
Non-wood forests are an important part of forest resources in China, which are associated with ecology, economy and social benefits. Non-wood forests play important roles in promoting the rural economic development and increasing farmers’ income in mountainous areas. Based on the comprehensive introduction of the development status of non-wood forests in China, this study summarizes the main research progress in various fields, including the collection and utilization of germplasm resources of non-wood forests, selection and breeding of improved varieties, mechanisms of high-yield cultivation, and processing and utilization of non-wood forest products. We propose that the key technologies for future non-wood forest research that will achieve technological breakthroughs are genome editing and molecular design breeding, using microorganisms to improve soil fertility, intelligent forestry, improving the ability to resist abiotic stress, optimizing the photosynthesis and improving the utilization rates of light energy, and the higher value addition products of non-wood forests. This review will provide useful information for non-wood forest industry development in China.
The unique geological landform and climatic characteristics of the Karst mountainous sites lead to slow soil development, shallow soil layer and severe soil erosion, which can be easily degraded into a rocky desertification landscape under the disturbance of human activities. The soil ecosystem in Karst mountainous areas is an essential basis for vegetation restoration. This paper analyzes the causes and control measurements of Karst rocky desertification, characteristics and problems in Karst mountainous soil. The impacts of different remediation techniques and treatments on the soil physical and chemical properties and microbial properties of the degraded Karst mountainous sites were summarized. The Meta-analysis method was used to compare the effects and mechanisms of biochar, chemical fertilizer, organic fertilizer, chemical and organic fertilizer mixture, biochar-based fertilizer, mulching, and biological crusts on soil physical properties, soil moisture, soil erosion, soil fertility, soil microbial community composition structure and diversity in the degraded Karst soils. Improving soil quality is one of the main technical measures to promote the ecological benefits of Karst vegetation restoration. The results showed that the biochar and biological crusting treatments could reduce soil bulk density, increase soil porosity and water retention, and then improve the soil quality. Biochar and biochar-based fertilizer applications had more significant effects on soil fertility improvement. Biological mulching could significantly reduce soil erosion degrees. Further research should be carried out in the identification of critical limiting factors for ecological restoration of the Karst degraded soil in different regions, the ecological remediation effects of the integrated soil improvement techniques on the Karst degraded soil, and the development of new biochar-based microbial fertilizers and soil carbon sequestration technology.
Economic growth has historically been significantly fueled by the mining industry. However, many abandoned mines which remain after mining activities have caused significant environmental damage. Based on the background of mine ecological restoration and the influence of microorganisms on soil and plants, the author divides microorganisms into five functional microorganism categories, including plant growth-promoting rhizobacteria, mineral-solubilizing microorganism, nitrogen fixing bacteria, rhizobia and mycorrhiza fungi. This review highlights the critical role of those functional microorganisms play in soil reconstruction and revegetation, summarizes the present issues with abandoned mines, and discusses common ecological restoration strategies. It is considered that: it is ideal for functional microbial inoculant to exist constantly because they can contribute positively to the ecosystem for a long time, and it is essential to extend the survival time of microbial inoculants and make their effects last for the ecological restoration of abandoned mines. In view of the special characteristics of different types of abandoned mine ecosystems, conducting research related to in situ inoculation of microorganisms in abandoned mines, engineering and transferring microbial traits into selected effective inter-rooted microbial isolates or entire inter-rooted microbial communities to produce functional microorganisms suitable for ecological restoration of different types of abandoned mines is an urgent problem to be solved for the ecological restoration of abandoned mines; and further revealing the long-lasting mechanisms of mineral solubilization by microorganisms and determining how to mobilize nutrients through mineral solubilization as an integral part of the whole soil community to more effectively and durably exert the mineral solubilization effect of microorganisms and secure the nutrient supply for plants.
Lake wetlands are the important part of wetlands in China, which plays an important role in reducing carbon emissions and mitigating global climate warming. However, the degradation of lake wetlands caused by global climate change and human activities limits the carbon sink function of wetlands. The status and causes of lake wetland degradation in China were combed, the effects of land use changes, biodiversity reduction and environmental pollution on the carbon sinks function of lake wetlands were analyzed, and the common lake wetland ecological restoration technology and the approaches to increase the carbon storage were summarized in this study. (1) Water environment remediation technology can improve wetland plants and soil carbon storage by removing endogenous and exogenous pollutants, improving the water quality of lake wetlands, and slowing down greenhouse gas emissions, and improve wetland plants and soil carbon storage. (2) Bioremediation technology can directly increase plant carbon storage, and then improve soil/sediment carbon storage through plant source carbon input and microbial action. Hydrologic and habitat restoration technologies can create favorable water levels and habitat conditions for bioremediation. The research about the biodiversity and its collaborative relationship and mechanisms with carbon sinks of lake wetlands, the impact of water quality on the carbon evolution of lake wetlands, the saturation carbon sink, and the measurement and approval system of lake wetlands should be further studied. The results are expected to provide a scientific basis for achieving the carbon peaking and neutrality goals of China.
Rising atmospheric CO2 concentration is recognized as the major driver for global climate warming. Thus, reducing atmospheric CO2 is also recognized as the main remediation method for climate change. Forestry practices play an essential role in atmospheric CO2 sequestration and global environmental engineering. Forestry carbon sequestration includes forest carbon sequestration and forest product carbon sequestration. Carbon sequestration in forests relies mainly on processes of ecosystem carbon balancing and forest product production, including photosynthesis and ecosystem net primary productivity, stabilization of soil organic carbon, and wood use efficiency and product lifespan. Forestry carbon sequestration can be achieved through (1) expanding forest areas with afforestation practices guided by the “matching trees with site or calcium” principle; (2) increasing forest net productivity with integrated forest management of water, nutrients, and pest or fire control; (3) enhancing the stabilization of soil organic carbon content by clay minerals; (4) promoting the use and improving the lifespan of forest products. At the global scale, an additional 1 Pg (C) of carbon can be sequestrated each year for 30 years by increasing forest area or net productivity by 3.4%, or by converting fuel wood to sawn wood or wood-based panels. Furthermore, reducing carbon loss from forest fire by a quarter or elevating soil organic carbon by 0.23% can also decrease carbon emissions by 1 Pg (C) each year. Carbon sequestration in forestry has great potential for reducing atmospheric carbon dioxide and mediating global climate warming.
Analyzing the value realization path of forestry carbon sink products can help realize the integration and win-win of ecological benefits, economic benefits and social benefits of forestry carbon sinks. Through the literature review and case inductive analysis, the related concepts of forestry carbon sink products were introduced, the value realization path of forestry carbon sink products was summarized, and the shortcomings of its development were explored. Finally, based on the current situation of academic research and practice development in China, we provide suggestions for future theoretical research and mechanism design. The authors defines the concept of forestry carbon sink finance, and believes that the value realization path of forestry carbon sink products can be summarized as the government ecological compensation path, the forestry carbon sink financial path and forestry carbon sink industrialization paths. These three paths are helpful to realize the value of forestry carbon sink products. However, the current lack of sustainable government ecological compensation in various countries, the urgent need to improve forestry carbon sink trading rules, weak willingness of financial institutions to participate in forestry carbon sink finance, and slow industrialization of forestry carbon sinks restrict the realization of the value of forestry carbon sink products. To improve the forestry carbon sink ecological compensation system, we suggest promoting the incorporation of forestry carbon sink products into the national unified carbon market, strengthening the theoretical and practical research on the forestry carbon sink financial path, improving the forestry carbon sink industry as the core industrial support policy, and strengthening the construction of the guarantee mechanism for the value of forestry carbon sink products, etc. These aspects will promote the realization of the value of China’s forestry carbon sink.
Water erosion was the focus and hot field of soil erosion research. It was of great significance to study the dynamics of soil organic carbon during erosion and deposition under water erosion for evaluating the “source & sink” effect of soil carbon. The study summarized the research status of soil carbon cycle under water erosion, expounds the research and methods of soil carbon mineralization in the process of soil water erosion, and clarified the dynamics of soil organic carbon in the process of soil water erosion from three aspects: the quantitative research of soil organic carbon mineralization, the redistribution of organic carbon and the influence of organic carbon mineralization. The main achievements of organic carbon in the process of soil water erosion at home and abroad are compared and analyzed. It is suggested that the whole process of water erosion, such as destruction, transportation and deposition, should be accurately analyzed and quantified in future research. On this basis, the response mechanism of carbon mineralization characteristics under the combined action of physics, chemistry and biology should be revealed, and the dynamics of soil carbon budget during water erosion should be comprehensively explored to quantify the contribution of soil erosion to the global soil carbon cycle.
With global warming, drought has become a serious issue in the world. Drought can significantly affect the soil carbon accumulation and transformation in forest ecosystems. Forest soil organic carbon (SOC) is the largest carbon pool in terrestrial ecosystems, and its dynamic changes significantly affect the global carbon cycle. Drought stress affects all processes of soil organic carbon dynamics, including the input of organic carbon from the above-ground and belowground litter and the transformation and decomposition of litter, and then causes changes in the soil carbon pool. Here, we reviewed the research progress of the effects of drought on soil organic carbon in forests. The results show that (1) short-term drought increases forest litterfall by promoting leaf shedding in advance, while long-term drought affects forest plant growth, reduces forest primary productivity, and thus decreases plant litterfall. To compensate for water loss, plants in mild and moderate drought increase fine root biomass to maintain plant vitality. In severe drought, plants lose self-repair ability, resulting in reduced fine root biomass and increased fine root mortality. On average, drought decreases forest litter (1.9%)and fine-root biomass(8.7%) worldwide, ultimately reducing the input of plant organic carbon to soil. (2) Drought can reduce the decomposition rate of litter(10% to 70%) by changing its chemical properties and stressing the soil animals and microorganisms responsible for its decomposition. Drought changes the carbon and nitrogen concentration of litters; causes accumulation of secondary metabolites such as cellulose, lignin and tannin; and changes the chemical components of root exudates, thus affecting the decomposition of litter. Moreover, drought results in the decrease of fungal biomass and abundance of soil fauna in decomposers, increases the predation pressure of decomposer animals, and decreases the activities of related microorganisms and enzymes, resulting in the decrease of litter decomposition rate.(3) Drought-driven changes in microbial community composition (the ratio of fungi to bacteria and of Gram-positive to Gram-negative-bacteria increased) result in the decrease of microbial biomass and activity, and drought reduces the feeding and enzyme activities of scavengers, which eventually lead to the decrease of soil organic carbon mineralization rate(10% to 50%).(4) The effects of drought on different components of soil organic carbon are different. Drought produces a smaller and more sensitive soil microbial biomass carbon (MBC) pool(2% to 30%), resulting in the accumulation of dissolved organic carbon (DOC) in surface soil(30%-60%). However, the effects of drought on SOC accumulation vary in different regions of the world. In subtropical forests, the effects of drought on SOC accumulation are mostly negative, while in tropical forests, the effects are positive. In general, drought may have little effect on the forest SOC pool, but reduces soil carbon turnover. Additionally, forest SOC turnover is not affected only by drought; temperature, species, and other factors work together in the turnover of SOC and accumulation. The simple superposition simulation may be single-or multi-factor in the real-world impact on soil carbon flux, which has certain differences. For example, the effect of increasing temperature and drought produce antagonism; the effect of their interaction on soil carbon input is lower than the superposition effect on soil carbon input, and the interaction effect of the two on soil carbon loss is not significant. We propose that it is important to conduct long-term observations, prolonging control experiment through simulating native environments and multi-factor comprehensive influence, to understand the effects of drought on the dynamic process and mechanism of soil organic carbon.
Cellulose is the most abundant polysaccharide in nature, which accounts for more than 50% of the carbon content in the plant kingdom. Cellulose is the main cell wall content in plants and plays a key role in weight bearing. The synthesis of cellulose is catalyzed by cellulose synthase components (CSCs) in the plasma membrane. The research advances on the type, structure, transcriptional regulation of CESA, and the structure, assembly, and traffic of CSCs were reviewed here. The plant cell wall was classified into the primary cell wall and the secondary cell wall. The CSCs involved in cellulose synthesis in different cell wall types are different. The proportion of CESAs in the CSCs varies according to the species. CESA stoichiometry occurs in equimolar amounts in the majority of plants, while in aspen tension wood the secondary cell wall CESA stoichiometry changed to 8∶3∶1. CSCs assemble in the Golgi and are secreted to the plasma membrane through the trans-Golgi network (TGN) compartment. The abundance and distribution of CSCs in the plasma membrane largely determine the oriented deposition of cellulose. Many key genes were found interacting with special CESA to recognize and regulate CSCs traffic. Plant hormones, such as brassinosteroids, can control the cellulose synthesis by regulating the expression of CESAs. In the future, gene-editing technology can be used to further work on CESA function, CSCs structure model, CESA stoichiometry in CSCs, the relationship between assembly and transport and cellulose synthesis speed in CSCs, and the transcriptional regulation of CESA to improve the regulation mechanisms of plant cellulose synthesis.
Insects, as a group of ectotherm animals, are extraordinarily susceptible to heat stress. Exploring the effects of heat stress on herbivorous insects can provide an important theoretical basis for monitoring the population dynamics of agricultural and forestry insect pests and predicting potential changes in their geographical distributions under the background of climate warming. From the aspects of individuals, interspecific interaction, populations and communities, we reviewed the research progress of the impacts of heat stress on herbivorous insects. Heat stress has negative effects on the growth, development, reproduction, physiology and biochemistry of herbivorous insects, which has evolved a series of strategies responding to heat stress by modifying morphology, behavior and related gene expression. The effects of heat stress on host plants, natural enemies and symbiotic microorganisms can also be transmitted to herbivorous insects through interspecific interactions, resulting in changes in the tertiary trophic relationships among host plants, herbivorous insects and natural enemies. Meanwhile, heat stress can also indirectly affect herbivorous insects’ population dynamics as well as their diversities and ecological functions in the natural communities, by influencing insect individuals and their interspecific interactions with other organisms, which may lead to large outbreaks or declines in the populations of herbivorous insects. Finally, the future research directions in this field are as follows: from the individual perspective, the treatment mode of high-temperature stress should be optimized, and environmental factors such as drought and precipitation should be comprehensively considered; long-term field monitoring of agricultural and forestry pest populations should be performed, and the influence of high temperature stress on the genes of insect participation in growth, development, and reproduction should be studied; at the interspecific relationship level, attention should be paid to the effects of high temperature stress on the complex and diverse food webs or intercroprising systems associated with insects; in addition, the effects of high temperature stress on the physiological characteristics and behavioral patterns of various insect species should be combined to determine the effects of elevated temperatures on insect communities.
The area of planted forests in China ranks first in the world, but the per capita consumption of timber is only 1/5 that the of developed countries. The dependence on foreign timber is colsed to 50%. Timber forests are of great significance to China’s timber and ecological security forest carbon sequestration and green development. However, due to single tree species, simple stand structure, and low level of biodiversity biological disasters occur frequently in timber forests. Among them, fungal diseases are responsible for the major biological disasters on timber forests in China. This study focuses on the scientific aspects such as the pathogenic mechanisms and green control, and reviews the etiology, occurrence characteristics, pathogenic mechanisms, and biological control by endophytes on the main fungal diseases on timber species in China. The epidemic monitoring, pathogen-host interaction, cultivation management, sustainable green prevention and control, and other integrated control strategies of major fungal diseases on timber forests in the future are prospected as well.
Although the history of bamboo resources utilization can be traced back to 7 000 years ago, the understanding of bamboo as a special group of Gramineae was not established until the late 18th century. Carl von Liné, the founder of modern plant classification, treated all bamboo species in the world as one species belonging to the genus Arundo (Arundo arbor) in his book “Species Plantarum”. It was not until 1789 that bamboo was separated from Arundo and the first bamboo genus, Bambusa, was established. Since its recognition as a distinct species from other grasses, there has been a wealth of literature addressing these aspects, including morphology, anatomy, systematics, physiology, ecology, cytology, genetics and molecular biology. However, systematic research on the occurrence, development and senescence of various organs of bamboo plants is still lacking. This article reviews and summarizes research on the developmental biology of the bamboo root, rhizome, culm, leaves and reproductive organs. We highlight what is insufficient or lacking in the field of bamboo developmental biology and what should be further investigated. We proposed to consider the entire process of cell division, differentiation and morphogenesis when studying the developmental biology of bamboo, and to investigate the dynamics of physiological and biochemical indices throughout the process to reveal the gene expression and signal transduction pathways that control each step of the entire developmental process.
Delayed autonomous self-pollination or delayed selfing is a reproductive way of autonomous self-pollination that occurs at the end of cross-pollination of a single flower in flowering plants. To complement the comprehensive data base of plant evolution and pollination biology, we provide a review of progress in the occurrence pathways, experimental research methods, and the “best of both worlds” reproductive assurance hypothesis of delayed selfing. We also discuss the adaptive significance of delayed selfing and suggest future research directions. The delayed selfing is present in 74 angiosperm species, and widely distributed in 61 genera and 43 families, of which 52 species occur by a single pathway and 22 species by two pathways. In a single pathway, the style curvature is the most common to cause the delayed selfing. Incomplete dichogamy and reduced herkogamy are the most common pathways promoting the delayed selfing occurrence. Observations of delayed selfing have mostly been done through pollination biology, and few studies have combined pollination biology with genetics to provide the most rigorous evidence for the occurrence of delayed selfing. The reproductive assurance hypothesis of delayed selfing suggests that it prioritizes securing cross-pollination and can aid in the reproductive success of plants when the pollination environment is unpredictable. Therefore, the delayed selfing is considered the “best of both worlds” mating system that combines the advantages of selfing and outcrossing. In addition, for ovule-less species, plants have sufficient prior pollination and fertilization after a single visit by insects, which also prevents the occurrence of delayed selfing to save plant resources for other purposes.
【Objective】To develop new genetic resourese and establishment techniques of the next generation seed orchard, the 4th generation candidate genetic populations of chinese fir (Cunninghamia lanceolata) (which was one part of the long term Genetic Improvement Program of Chinese fir, organized by the Nanjing Forestry University-Fujian Province Cooperative)were created by a series of planed intraspecific crossing, and then the full-sib progeny testing and traits evaluation has been conducted continuously, since 2006. The establishment of the 4th generation orchard for seed production were initiated in 2016. In this study, a 12-year-old full-sib progeny testing was investigated and analyzed systematically, to provide detail genetic information and excellent parents selected for the 4th generation seed production orchard. 【Method】The tree height of 1-12 a, diameter at breast height (DBH) of 4, 5, 6, 9 and 12 a of full-sib progeny testing was measured, and the average volume per tree by family was calculated. The best individual trees within all the family plot were selected, and the wood increment core samples were collected at DBH (1.3m) to determine basic wood density and dark-brown heartwood proportion. The annual mean value and coefficient of variation on growth traits were used to evaluate the stability of family growth traits. The genetic variance and heritability was estimated for all observed traits. The effects of different stand ages, different effects of selection proportion and early selection on the accuracy and genetic gain was compared year by year, respectively. Finally, the excellent full-sibling families and superior individual trees within the family was selected and the genetic gain to be predicted, combining with their single tree volume and wood character.【Result】1) The results showed that the family mean of the tree height, DBH, volume growth (single tree), wood basic density and the proportion of dark-brown heartwood was 12.63 m, 15.2 cm, 0.136 8 m3, 0.328 0 g/cm3 and 40.76%, respectively. The genetic variance was extremely significant statistically for all the characters in the testing, and it was means that the true genetic differences was existed in the 4th candidate populations. 2) The family narrow heritability was 0.246, 0.358 and 0.329 for tree height, DBH and single tree volume, and it was 0.464, 0.687 and 0.680 for re-selected elite trees, respectively. Based on the optimization benchmark of volume growth, and basic wood density and the proportion of dark-brown heartwood, 10 excellent families and 19 elite trees within the family were selected. 3) The mean was 13.34 m, 17.0 cm, 0.176 3 m3, 0.320 2 g/cm3 and 40.76% for tree height, DBH, single tree volume, wood basic density and proportion of dark-brown heartwood of selected family, respectively. The volume genetic gain was 6.14%-21.60% for selected families, and 58.62%-178.20% for 19 excellent single trees. The mean of wood basic density was 0.363 3 g/cm3 for selected families, and 0.476 4 g/cm3 for the best selected individual. It was increased by 10% and 12.78% over the family mean for basic wood density and proportion of dark-brown heartwood traits. 4)The stability of tree height, DBH and volume growth, effects of selection proportion on genetic gain, early-later correlation of volume growth and early selection ages was also analyzed comprehensively. Setting volume growth as a comprehensive trait of tree height and DBH, and family selection proportion at 15%, the conformity degree of the selected family and the genetic gain for volume growth was the highest at 12 a, whatever the early selection was processed in 4, 5 or 6 a. This indicates that the early selection based on the volume growth performance of juvenile plantation, is not only feasible and effective in the 4th generation of genetic improvement of Chinese fir, but also the breeding cycle could be reduced greatly. 【Conclusion】there were abundant genetic variations on growth and wood properties from one candidate population for the 4th generation genetic improvement of Chinese fir. And these excellent families and re-selected elite individuals with a higher genetic gain in volume growth, basic wood density and proportion of dark-brown heartwood are important parental sources for the 4th generation seed orchard establishing, and also the genetic resourese of excellent clonal selection in the next rotation of genetic improvement of Chinese fir.
【Objective】Poplar trees are important for timber production, ecological protection and carbon sequestration, and also serve as a model for forest genetic research. The construction of poplar pangenome and analysis of genomic variations will provide a theoretical guidance for poplar precision breeding and pan-genome research of forest trees. 【Method】All published high-quality poplar genome sequences were collected for a comparative genomic analysis. Both small genomic variations and large structural variations were identified and compared. Gene-based and graph-based pan-genomes were constructed, respectively. 【Result】Genomic sequences of eight poplar species and three diploid or triploid poplar hybrids were collected. The three hybrids contained seven haplotype subgenome sequences. These sequences represented the genomic characteristics of the four poplar Sections well. The comparative genomic analysis showed that there were many structural variations among poplar genomes. In the gene-based Populus pan-genomes, syntenic core genes, nonsyntenic core genes, softcore genes, dispensable genes, and private genes account for 12.5%, 34.9%, 31.4%, 16.5% and 4.7% of the total genes, respectively. Among them, dispensable genes exhibit a high functional diversity. Based on the variations of genome sequences, the graph-based poplar pangenome was constructed, which greatly improved the efficiency of variation detection using NGS data. Two genomic loci associated with phenology were identified through variation hotspot analysis of pan-genome. 【Conclusion】A large amount of genomic structural variations were observed in the genomes of Populus genus, which increase the diversity of gene regulation and thus affect the growth traits of poplar trees. The genomic structural variations among poplar Sections may be related to phenological adaptation. Due to the genomic complexity of forest trees, several aspects need to be considered during the construction of forest pangenomes, such as the agreement of included genomes and research objectives. The results from gene- and graph-based pan-genomes can be combined to explore the genomic variation and evolution of forest trees.
【Objective】Stearoyl-ACP Δ9 desaturase (SAD) is a key enzyme that determines the composition of fatty acids. The whole-genome identification of Idesia polycarpa SAD genes can provide targets to improve fatty acid compositions by genetic methods.【Method】HMM and Blastp were used to identify IpSAD genes in the I. polycarpa genome. The gene structures, phylogenetic relationship, conserved motifs, physicochemical characters of IpSADs, and cis-regulatory element in these gene promoters were analyzed and predicted by MEGA X, MEME and PlantCare online software, respectively. The MCSCANX software was used to reveal the common linear relationship of SAD genes in I. polycarpa and P. trichocarpa. The tissue expression pattern of IpSAD genes was constructed according to RNA-seq, and the function of these genes was identified by a virus-induced gene silencing (VIGS) system.【Result】(1)A total of seven IpSAD genes (IpSAD1-7) were identified in the I. polycarpa genome, and these family members shared high sequence similarity and conserved domains. (2)Aphylogenetic tree indicated that IpSAD members were divided into three clades, which were consistent with the classification of the homologs in Arabidopsis thaliana. In particular,IpSAD2, IpSAD3 and IpSAD4 were closer to AtSSI2, which is the key enzyme of oleic acid biosynthesis. (3)The cis-regulatory elements in the promoters of IpSAD genes included elements of light and abscisic acid responses. (4)These IpSAD genes were divided into three categories according to their tissue expression patterns. The IpSAD genes in Classes Ⅰ and Ⅱ were expressed with a low level in most tissues, whereas Class Ⅲ genes showed a high level in all tested tissues. (5) Silencing IpSAD genes using VIGS significantly reduced the oleic acid content of leaves.Remarkably, the oleic acid content in IpSAD3 silenced leaves was decreased by up to 76%.【Conclusion】The characteristics of each IpSAD gene was clarified, and their functions in oleic acid synthesis were determined. Our findings can aid in the investigation of the biosynthesis mechanisms of oleic acid and total oil in I. polycarpa.
【Objective】Root exudates play an important role in the plant interspecific relationship. The effects of host root exudates and chemicals on growth, root development, nutrient accumulation and photosynthetic characteristics of hemiparasitie Santalum album seedlings were studied. The superior host root exudates or several chemicals were screened to provide a scientific guidance for cultivating S. album seedlings.【Method】Under greenhouse conditions, we performed the pot experiment to determine whether root exudates (Acacia confusa, Bischofia polycarpa, Dalbergia odorifera, Dracontomelon duperrereanum and S. album) and haustorium-inducing chemicals (2,6-dimethoxy-p-benzoquinone (DMBQ), formononetin, quercetin and syringaldehyde) could promote the growth and root development of S. album seedlings. The growth indices (height, diameter and biomass), root morphology (total root length and root surface area), nutrient (N, P, K) contents, and photosynthetic characteristics (SPAD values, photosynthetic rate (Pn), stomatal conductance (Gs), transpiration rate (Tr)) of S. album seedlings were measured after a 3-month treatment.【Result】The height, shoot and root biomass of S. album seedlings exhibited the significantly greater growth when treated with Dalbergia odorifera root exudates, DMBQ and syringaldehyde. The total root length, root surface area and length of thin fine roots were significantly greater in S. album seedlings treated with 4 root exudates (except for B. polycarpa) and 4 chemicals than those of the control treatment. The exogenous signal substance could promote N, P and K absorption of S. album seedlings, especially for Dalbergia odorifera root exudate and DMBQ. Root exudates of Dalbergia odorifera and A. confusa, DMBQ and syringaldehyde induced significantly higher SPAD values. Dalbergia odorifera root exudate and 4 chemicals could induce significantly higher photosynthetic characteristics of S. album seedlings. The correlation analysis shows that there are significant and strong correlations between growth indices, physiology indices and root growth (except for thick fine root and coarse root length). Haustoria number of S. album seedlings are significantly correlated with the total the root length and root surface area, indicating that the haustorium development of S. album is closely related to root growth.【Conclusion】The application of root exudates of superior host and/or haustorium-inducing chemicals could effectively promote root development, nutrient absorption, and photoautotrophic capability of S. album seedlings. Our results provide insights into S. album nursery in south China.
【Objective】Mint(Mentha canadensis) is a medicinal and edible herb of the Mentha genus in the Lamiaceae family that is rich in medicinal essential oil. WRKY family is a type of plant-specific transcription factor family, and plays an important role in regulating plant secondary metabolism. In this study, MhWRKY57 gene was cloned from mint, and its gene and amino acid characteristics, subcellular localization, transcriptional activity and tissue expression were studied. Additionally, the gene expression levels of MhWRKY57 with essential oil biosynthesis-related gene MhGPPS-s under methyl jasmonate treatment were analyzed, which provides a theoretical basis for revealing the molecular mechanism of MhWRKY57 regulating mint essential oil biosynthesis responding to jasmonic acid signal.【Method】 Based on the transcriptome database of mint treated with methyl jasmonate, a WRKY transcription factor gene significantly induced by methyl jasmonate was screened and then cloned by RT-PCR, sequenced, and named MhWRKY57, according to homology. The gene and amino acid characteristics of MhWRKY57 were analyzed by bioinformatics, and the phylogenetic tree was constructed with MEGA7 by the maximum likelihood method for a homology analysis. The subcellular localization of MhWRKY57 was demonstrated using a tobacco leaf transient expression system combined with green fluorescent protein (GFP) fusion expression system followed by laser confocal scanning microscopy (LCSM) to detect the fluorescence signal. To verify the transcriptional activity of MhWRKY57, the MhWRKY57 coding sequence was cloned into the pBD vector so that transcriptional activation could be assayed in a yeast two-hybrid system. The expression patterns of genes in various tissues and induced by methyl jasmonate were analyzed by quantitative real-time PCR (qRT-PCR). 【Result】The coding sequence (CDS) of MhWRKY57 was cloned, which contained an open reading frame with 831 bases and encoded 276 amino acids. The secondary structure of MhWRKY57 was predicted, including mainly random coil, then alpha helix, extended strand and beta turn. The amino acids of MhWRKY57 were predicted to have 34 phosphorylation sites in which the serine may be mainly phosphorylated. MhWRKY57 is a non-transmembrane protein with certain hydrophilicity and instability. The amino acid sequences of WRKY57 ortholog proteins from M. canadensis and other ten plant species were used for a cluster analysis, and the results showed that MhWRKY57 was closer to soybean Glyma.01G056800.2.p than other WRKY57 ortholog proteins in the evolutionary relationship. The domain analysis and amino acid sequence alignment showed that MhWRKY57 was a typical transcription factor that belonged to the WRKY family and contained a conserved WRKYGQK domain at the N-terminus, and an incomplete C2H2 zinc-finger structure at the C-terminus. The MhWRKY57 protein was predicted to be located in the nucleus, and transiently co-expressed in onion epidermal cells of MhWRKY57-GFP fusion protein together with the OsD53-RFP, which is a nuclear localized marker protein. The subcellular distributions of these two fusion proteins were merged further, indicating that MhWRKY57 was a nuclear-localized protein. The transcriptional activity verification of MhWRKY57 was performed on SD/-Trp and SD/-Trp-His-Ade media using Y2H Gold yeast cells. The yeast strains harboring the BD- MhWRKY57 plasmid could grow on both SD/-Trp and SD/-Trp-His-Ade media, whereas the yeast strains transformed with the pBD empty vector could only grow on SD/-Trp medium, which suggested that MhWRKY57 had transcriptional activation activity. The tissues of young and mature leaves, flowers, stems and roots were prepared individually to be used for the total RNA extraction, and then for a tissue expression analysis using qRT-PCR. The qRT-PCR analysis showed that MhWRKY57 gene was expressed in young and mature leaves, flowers, stems and roots, and the highest expression level of MhWRKY57 gene was in flowers, followed by roots, stems, mature leaves and young leaves. The mint seedlings cultured in water were treated with 0.2 mol/L MeJA to analyze the response of MhWRKY57 gene in roots and leaves to MeJA, respectively. The expression of MhWRKY57 gene in roots and leaves was induced most significantly at 12 h after treatment, while the expression was down regulated to the control level after 24 h of treatment. In addition, the expression levels of MhGPPS-s gene in leaves and roots, which plays an important role in mint essential oil biosynthesis under treatment of 0.2 mol/L MeJA, were also detected. Compared with the control, the mRNA levels of MhGPPS-s gene in leaves were evidently enhanced at 9 and 12 h after treatment, while those of MhGPPS-s gene in leaves were enhanced evidently at 2 and 4 h after treatment. These results indicated that the expression of MhGPPS-s and MhWRKY57 genes were both induced by MeJA. 【Conclusion】 MhWRKY57 is widely expressed in major tissues of mint and encodes a transcription factor, which is located in the nucleus. MhWRKY57 is a typical WRKY family protein that possesses a conserved WRKY domain and has transcriptional activation activity. Considering that WRKY family genes play important roles in secondary metabolism and MhGPPS-s gene functions in the biosynthesis of mint essential oil, both the expression of MhWRKY57 and MhGPPS-s genes in mint leaves can be significantly induced by MeJA, which implies that MhWRKY57 gene may play a role in the biosynthesis of mint essential oil by regulating the expression of MhGPPS-s gene in response to jasmonic acid signal.
【Intention】The Yangtze River Delta has formed many scenic areas with its rich natural and cultural landscapes, which impacts the construction of ecological protection patterns and the development of regional green integration. The quantitative analysis of the distribution and accessibility characteristics of scenic spots in the Yangtze River Delta, the construction of a research framework on the spatial distribution and accessibility of scenic spots at the regional scale, and the overall analysis of the spatial structure of the scenic spots system in the Yangtze River Delta region will help rationalize the use of scenic resources and promote the sustainable development of the region. 【Method】The spatial distribution and accessibility of 123 scenic areas in the Yangtze River Delta were analyzed using ArcGIS platform and mathematical models considering the multi service radius and the level as well as the type of scenic areas.【Result】(1) The Yangtze River Delta scenic areas are “dense in the south and sparse in the north” and range from random to dispersed. (2) The discrepancy of accessibility distribution is significant, and the spatial polarization varies under three search radius. With the increase of the radius threshold, the accessibility level has an overall upward trend. In addition, the accessibility aggregation characteristics of counties are higher under the three radii, and the hot areas are mainly distributed in Huangshan, Xuancheng, Lishui, Hangzhou, Jinhua, Suzhou and Wuxi, while the cold areas appear in Shanghai and its surrounding areas. (3) Among the different levels, the accessibility of national scenic areas is better than that the of provincial scenic areas. The accessibility of independent scenic areas is better than the combined urban and scenic areas. (4) Accessibility is affected by different objective factors, and the degree of correlation is in the order of: distribution density of scenic areas > population distribution > road network density. 【Conclusion】The distribution and accessibility of scenic areas in the Yangtze River Delta show significant regional differences. This research provides a reference for the integration of resources, systematic management and regional tourism development in the scenic areas in the Yangtze River Delta.
Eucalypts are the common name for trees from the three genera Eucalyptus, Angophora and Corymbia within family Myrtaceae. They have been introduced into China for more than 130 years and are currently an important choice of trees for industrial plantations. In China, genetics and breeding studies of eucalypts began with seed orchard establishment in the 1960s, followed by provenance trials in the late 1970s. Since then, some important techniques have shown significant impacts on accelerating the genetics and breeding studies of eucalypts, mainly including: (1) seed orchard management, especially in the early years, which has promoted the sexual propagation of those eucalypt species with difficulty in vegetative propagation; (2) cutting and tissue culture developed in the 1990s that have enhanced the selection and cultivation of superior clones; (3) molecular markers arisen in the late 1990s that have started the new era of eucalypt molecular breeding; (4) genetic transformation initiated in the 2000s that has provided a novel approach for creating new varieties; and (5) genome editing that is under attempt and has casted great application potentials. As breeding strategy and germplasm are concerned, breeding strategies and breeding plans have formulated for several species, in which within-species recurrent selection and hybrid clone selection were taken into account on such economic traits as volume growth, wood density, pest and disease resistance and typhoon tolerance; and more than 3 000 families of about 200 species collected for germplasm conservation. Great progresses have been made in eucalypt genetics and breeding studies in China, mainly including: (1) recurrent selection over generations accomplished for major species, with only E. urophylla reaching the third generation; (2) hybrid breeding with achievements of such widely planted hybrid clones as DH32-29 and DH33-27; (3) clonal breeding plus vegetative propagation technique development for tremendous contribution to clonal forestry; (4) development of several types of molecular markers, including the next-generation sequencing based markers, and marker-based delineation of genomic loci linked/associated with growth, wood properties and/or stress response detected in E. urophylla and other five species; (5) genes cloned and expression analyzed for stress response, phytohormone and wood formation, including some with promising application potentials; and (6) optimization of genetic transformation system, successful production of transgenic plants and attempt of genome editing. Nevertheless, some challenges remain herein, including genotype × environment interaction complexity and high-quality genome and pan-genome sequence absence as well as germplasm erosion, new clone scarcity, few de novo cloned genes with breeding values, genomic selection uncertainty and further upgrading of genetic transformation technology. Eucalypt genetics and breeding studies have played a pivotal role in China’s forestry development, and breakthrough may be made in advanced generation improvement, long-term germplasm evaluation, heterosis mechanism exploration and utilization, genomic selection application and trans-genic and genome editing techniques.
Willows are a prominent group of native tree species in China, mainly due to the large quantities, wide distribution, abundant variation, fast growing and easy propagating. Willows have extensive and critical ecological and economic values as multi-functional tree species that serve for landscape planting, ecological protection, bioremediation and as an important wood source for timber, bioenergy and weaving. In recent years, willow research has developed rapidly in China. A large number of improved varieties or new varieties have been selected through conventional breeding, and major breakthroughs in genetics and genomics made China as a world leader in these fields. In this paper, we systematically summarize the progresses of willow mainly focused on taxonomy and distribution, germplasm collection, conservation as well as evaluation, genetic improvement, and molecular genetics around 60 years in China. Meanwhile, we analyzed the problems on genetic breeding at present and discussed the major prospects in future in order to promote the level of willow research in China, provide useful information for genetic breeding research of other woody plants.
Oaks are important economic and ecological tree species in the northern Hemisphere, and are colloquially known as the “tree of life” or the “frame of civilization”. The publication of several oak genomes, such as those of Quercus robur, Q. lobata and Q. acutissima, has a profound impact on oak biology. In the past five years,numerous topics in oak biology have been investigated, including the systematic evolution and species identification, gene introgression and adaptive evolution, landscape genomics and ecological conservation, biological coexistence and interaction mechanism, secondary metabolism and growth and development, DNA methylation and epigenetic regulation, genes and longevity mechanisms. The expected development trends include four aspects: highlighting the in-depth application of oak genome resources, promoting extension of oak study systems, emphasizing topics in genetics and development for utilization of oak resources, and highlighting themes in ecology and evolution for conservation of oak forests.
Color is an important flower trait that plays a key role in ornamental horticulture, reproductive ecology, and species evolution of flowering plants. The key determinants of flower coloration in flowering plants are synthesis and deposition of flower pigments. As a family of natural pigments, carotenoids not only have nutritional and pharmacological properties, but also are the main chromogenic pigments during flower coloration of many flowering plants. Here, we review the pathway for carotenoid metabolism and its related genes and summarize the effects of carotenoid metabolic gene expression and transcriptional regulation on the carotenoid accumulation and flower coloration. At present, it is well known that the expression of carotenoid metabolic genes in flowers is closely related to the carotenoid accumulation and flower coloration; however, research on the mechanisms of transcriptional regulation of these genes in flowers is still in the early stage. In particular, flowers seem to adopt different strategies for fine-tuning carotenoid biosynthesis and accumulation compared to the other organs like leaves and fruits. Additionally, no consensus has been found among different plant species. Based on the current research progress, we prospect the future research on the regulation mechanisms of carotenoid-mediated flower coloration. With the rapid development of high-throughput omics technologies and molecular biology techniques, we suggest the combination of multi-omics such as genomics, transcriptomics, metabolomics and the latest single-cell omics and spatial omics, and genetic transformation and genome editing technology represented by CRISPR/Cas9 to de novo construct the specific molecular regulatory network of carotenoid metabolism during flower coloration of a variety of plants. We hope to provide a useful reference for the further research on flower color variation and evolution mediated by carotenoids and flower color breeding.
Information technology is an important driving force for the development of human civilization, and it is also one of the fastest growing and most influential high-techs in the world today. With the wide application of modern information technology in the field of forestry, smart forestry has become the route one must take for the development of modern forestry. Smart forestry is the deep integration of new generation information technologies such as Internet of Things, big data, cloud computing, artificial intelligence, mobile Internet and 3S technology, intelligent equipment as well as forestry production and management businesses such as and forest breeding, forest cultivation, forest management and forest protection. The development of smart forestry in China is a milestone in the development of modern forestry. The author introduces the background, connotation, characteristics, theoretical basis and research methods of smart forestry, as well as top-level design, project deployment and implementation, scientific research platform construction and talent training for smart forestry development; the research status of key core technologies of intelligent forestry, such as forestry intelligent perception, spatial information technology, big data and cloud computing, virtual reality and intelligent equipment technology, are systematically introduced. The application progress of smart forestry in forest tree genetics and breeding, forest precision silviculture, forest resource monitoring and management decision-making, forest fire monitoring and prediction, pest control, and wildlife protection were further introduced. Finally, the development goals of smart forestry in the future are pointed out, and the main development directions of smart forestry technology system are prospected. The author believes that the development of smart forestry needs to further promote the research, development and application of intelligent algorithms and hardware, as well as to strengthen the research of its theoretical basis. At the same time, it is also necessary to integrate modern data mining, model simulation and intelligent analysis technologies into the forestry production business process on the basis of obtaining accurate multi-source data, to provide services for the whole industry chain of forestry production and lead the high-quality development of forestry.
Soil salinization has become a global issue in recent years, and is one of the most important environmental factors restricting forest growth. Therefore, it’s of great significance to understand the salt-tolerant mechanisms of trees and improve techniques of comprehensively using saline-alkali land for soil utilization and ecological environment protection. Here, we discuss effects of salt stress on forests, including growth restriction, photosynthesis inhibition, metabolism turbulence and ion imbalance, which leads to a low yield of plantation and insufficient efficiency of soil utilization. Additionally, we review the integrated system evolved by forests focusing on the host metabolic regulation and interaction with microbiota to alleviate damages to provide a theoretical basis for exploring forestation techniques and plantation cultivation on saline-alkali land.
