【Objective】To analyze the phylogenetic relationships and evolutional patterns of pollen morphology in Tsuga, we observed and compared the pollen characteristics of all 10 extant species of Tsuga along with pollen fossils.【Method】Pollen morphology was examined using scanning electron microscopy (SEM), and hierarchical cluster analysis (HCA) was conducted using seven quantitative indicators and one qualitative indicator.【Result】Tsuga pollens typically exhibits characteristics of the N1P3C1 type, with a leptoma on the distal face. The equatorial length ranges from 21.20 to 58.00 μm, predominantly lacking sacci but occasionally with echinae saccate forms. The pollen surface is typically warty or sparsely micro-warty, with spines or without. According to the hierarchical cluster analysis, Tsuga could be divided into three categories: ①saccate but lacking echinae type: T. mertensiana and Nothotsuga longibracteata; ②lacking sacci and echinae type: T. caroliniana, T. canadensis and pollen fossil T. sp.2; ③lacking sacci but echinate type: T. heterophylla, T. ulleungensis, T. diversifolia, T. forrestii, T. sieboldii, T. dumosa, T. chinensis and pollen fossil T. sp.1, T. sp.3.【Conclusion】Pollen morphology in Tsuga has evolved from saccate to non-saccate forms, and from lacking spines to possessing spines. These pollen characteristics are closely related to geographic distribution, indicating similarity among pollen from the same regions. The clustering analysis based on pollen morphology largely aligns with molecular phylogenetic trees, offering a method to distinguish extant species and fossils of Tsuga and providing valuable insights for phylogenetic studies of Tsuga.
【Objective】To test whether Sorbus ser. Folgnerianae is a monophyletic group and to reconstruct the phylogenetic relationship among three species, S. dunnii, S. folgneri and S. hemsleyi.【Method】Morphological characteristics of leaves, flowers and fruits of Ser. Folgnerianae species were compared through specimen examination and field observation. Phylogenetic relationships within Ser. Folgnerianae were analyzed based on the comparison of the plastid genomes, repeat sequences, sequence variations of the five plastid genomes newly sequenced including three Ser. Folgnerianae species and S. megalocarpa from Sect. Aria, together with other plastid genomes available in this genus, using representatives of related genera in Rosaceae and Barbeya oleoides (Barbeyaceae) as the outgroups.【Result】Species of Ser. Folgnerianae can be easily distinguished from each other in the number of styles, color of anthers, fruit morphology and the persistence of calyx. Plastid genomes of five samples have a similar structure, gene content and organization. This sizes of plastid genomes range from 159 898 to 160 755 bp, with the GC contain range between 36.4% and 36.6%. All plastid genomes contain 113 unique genes (79 protein-coding genes, 30 tRNA genes and four ribosomal RNA genes). The IR region has two pseudogenes, rps19Ψand ycf1Ψ, with different extension lengths. 48-54 simple sequence repeats (SSRs), 36-49 long repeats sequences (LRSs) and 20 highly variable regions in the noncoding regions are identified as the most promising potentially variable makers for population genetics, species delimitation and phylogenetic studies. Phylogenetic analyses under ML/BI indicated that Sorbus is polyphyletic and the six sections within it are all monophyletic. Although, three sampled species of Ser. Folgnerianae are clustered in one group, S. Alnifolia of Ser. Alnifolia is more closely related to S. dunnii and S. folgneri than S. hemsleyi.【Conclusion】Sorbus ser. Folgnerianae is not monophyletic. Morphological characteristics and plastid genome analysis are effective in understanding the phylogenetic relationship in Ser. Folgnerianae.
【Objective】This study selected core genomic single-nucleotide polymorphism (SNP) loci to establish a rapid SNP genotyping method on the KASP platform, and to construct molecular IDs for Osmanthus fragrans cultivars. This study provides a theoretical foundation for identifying, tracing and protecting the intellectual property of O. fragrans cultivars.【Method】Field surveys were conducted to investigate key phenotypic characteristics of O. fragrans cultivars. Following two rounds of rigorous screening, we identified a set of core SNP markers capable of completely distinguishing previously sequenced cultivars. Subsequently, we analyzed the polymorphic information content (PIC) and expected heterozygosity (He) of each SNP locus. Using the genome sequences of ‘Rixianggui’ as a reference, species-specific KASP primers were designed for PCR amplification. Based on the genotyping results, we constructed cultivar DNA fingerprints and assessed the efficiency of core SNP markers for cultivar identification. Molecular IDs for O. fragrans cultivars were established by integrating phenotypic information codes with molecular fingerprint codes.【Result】We retained a total of 14 core SNP loci from genomic SNPs that fully discriminated the sequenced cultivars. The PIC values of these loci ranged from 0.246 to 0.375, with an average of 0.335, and the He indices ranged from 0.288 to 0.500, averaging 0.431. The KASP primers designed for these core SNP loci produced accurate genotyping results, enabling us to construct DNA fingerprints capable of distinguishing all 90 tested cultivars, including those not previously sequenced. Each cultivar was assigned a molecular ID composed of 34 digits.【Conclusion】In conclusion, 14 core SNP loci (SNP1 to SNP14) were identified that effectively discriminate among at least 90 O. fragrans cultivars. Unique molecular ID codes were constructed using DNA fingerprint codes along with serial codes derived from cultivar group types and phenotypic characteristics. Finally, barcode and quick response (QR) codes were generated for each cultivar.
Five species (Isotrema hyperxanthum (X.X. Zhu & J.S. Ma) X.X. Zhu, et al., Dalbergia velutina Benth., Trichosanthes rubriflos Thorel ex Cayla, Albizia corniculata (Lour.) Druce, Capparis cantoniensis Lour.,) and one variety (Ventilago leiocarpa var. pubescens Y.L. Chen & P.K. Chou) of liana were reported as new records from Hunan Province, China. The voucher specimens were deposited in the Herbarium of the Central South University of Forestry and Technology, Hunan, China.
【Objective】Professor Wan-Chun Cheng conducted the first systematic classification study of gymnosperms in China. In 1978, the results were published in Volume 7 of the Flora Republicae Popularis Sinicae, introducing a novel classification system for gymnosperms in the country. This seminal work systematically organized gymnosperm species in China, establishing a strong foundation for subsequent research in gymnosperm classification in the region.【Method】Building on the latest gymnosperm classification system proposed by Professor Yang Yong in 2022, this study compiled a new species checklist of gymnosperms in China. Data from Volume 7 of the Flora Republicae Popularis Sinicae (FRPS), Flora of China Vol. 4 (FOC), and the Catalogue of Life in China 2023 were reviewed, along with recent relevant literature.【Result】The results revealed that China is currently home to 267 wild gymnosperm species, distributed among 37 genera within nine families (including 27 infraspecific taxa). We propose two new combinations: Sabina carinata (Y.F. Yu & L.K. Fu) Y. Yang and Meng Li and Sabina arenaria (E.H.Wilson) W.C. Cheng and W.T. Wang ex Y. Yang and Meng Li.【Conclusion】This study enhances the species catalog of wild gymnosperms in China, serving as a crucial reference for further botanical classification research and conservation efforts aimed at native gymnosperms.
