Preserving genetic diversity is crucial for the long-term survival of wild plant species, yet many remain at risk of genetic erosion due to small population sizes and habitat fragmentation. Here, we present a comparative genomic study of the critically endangered Oreocharis esquirolii (Gesneriaceae) and its widespread congener O. maximowiczii. We assembled and annotated chromosome-level reference genomes for both species and generated whole-genome resequencing data from 28 O. esquirolii and 79 O. maximowiczii individuals. Our analyses reveal substantially lower genetic diversity and higher inbreeding in O. esquirolii, despite its overall reduced mutational burden. Notably, O. esquirolii exhibits an elevated proportion of strongly deleterious mutations relative to O. maximowiczii, suggesting that limited opportunities for purging have allowed these variants to accumulate. These contrasting genomic profiles likely reflect divergent demographic histories, with O. esquirolii having experienced severe bottlenecks and protracted population decline. Collectively, our findings highlight the critically endangered status of O. esquirolii, characterized by diminished genetic diversity, pronounced inbreeding, and reduced ability to eliminate deleterious alleles. This study provides valuable genomic resources for the Gesneriaceae family and underscores the urgent need for targeted conservation measures, including habitat protection and ex situ preservation efforts, to mitigate the extinction risk facing O. esquirolii and potentially other threatened congeners.

Andromonoecy is a rare sexual system in plants. The function of additional male flowers in andromonoecious species has been widely discussed; however, few studies have taken offspring fitness into account. In addition, little is known about the mechanisms that maintain andromonoecy in autogamous species. In this study, we compared morphology, pollinator preference, pollen production and export, siring ability, natural siring success, hundred seed dry weight, and seed germination rates between male and hermaphroditic flowers in an endangered autogamous andromonoecious species, Sagittaria guayanensis. Male flowers, which are larger than hermaphroditic flowers, required fewer resources to produce. Pollinators visited male flowers more frequently than they visited hermaphroditic flowers. In addition, pollen production and export were higher in male flowers. Hand pollination demonstrated that siring ability did not differ between flower type. However, the natural siring success of male flowers was triple that of hermaphroditic flowers. The seeds sired by male flowers performed better than those sired by hermaphroditic flowers, with greater dry weight and higher germination rate. In conclusion, male flowers may be superior pollen donors for outcrossing. The maintenance of andromonoecy in S. guayanensis may result from the better performance of male flowers in male function compared to that of hermaphroditic flowers.

Understanding genome-wide diversity, inbreeding, and the burden of accumulated deleterious mutations in small and isolated populations is essential for predicting and enhancing population persistence and resilience. However, these effects are rarely studied in limestone karst plants. Here, we re-sequenced the nuclear genomes of 62 individuals of the Begonia masoniana complex (B. liuyanii, B. longgangensis, B. masoniana and B. variegata) and investigated genomic divergence and genetic load for these four species. Our analyses revealed four distinct clusters corresponding to each species within the complex. Notably, there was only limited admixture between B. liuyanii and B. longgangensis occurring in overlapping geographic regions. All species experienced historical bottlenecks during the Pleistocene, which were likely caused by glacial climate fluctuations. We detected an asymmetric historical gene flow between group pairs within this timeframe, highlighting a distinctive pattern of interspecific divergence attributable to karst geographic isolation. We found that isolated populations of B. masoniana have limited gene flow, the smallest recent population size, the highest inbreeding coefficients, and the greatest accumulation of recessive deleterious mutations. These findings underscore the urgency to prioritize conservation efforts for these isolated population. This study is among the first to disentangle the genetic differentiation and specific demographic history of karst Begonia plants at the whole-genome level, shedding light on the potential risks associated with the accumulation of deleterious mutations over generations of inbreeding. Moreover, our findings may facilitate conservation planning by providing critical baseline genetic data and a better understanding of the historical events that have shaped current population structure of rare and endangered karst plants.

Global climate change has increased concerns regarding biodiversity loss. However, many key conservation issues still required further research, including demographic history, deleterious mutation load, adaptive evolution, and putative introgression. Here we generated the first chromosome-level genome of the endangered Chinese hazelnut, Corylus chinensis, and compared the genomic signatures with its sympatric widespread C. kwechowensis-C. yunnanensis complex. We found large genome rearrangements across all Corylus species and identified species-specific expanded gene families that may be involved in adaptation. Population genomics revealed that both C. chinensis and the C. kwechowensis-C. yunnanensis complex had diverged into two genetic lineages, forming a consistent pattern of southwestern-northern differentiation. Population size of the narrow southwestern lineages of both species have decreased continuously since the late Miocene, whereas the widespread northern lineages have remained stable (C. chinensis) or have even recovered from population bottlenecks (C. kwechowensis-C. yunnanensis complex) during the Quaternary. Compared with C. kwechowensis-C. yunnanensis complex, C. chinensis showed significantly lower genomic diversity and higher inbreeding level. However, C. chinensis carried significantly fewer deleterious mutations than C. kwechowensis-C. yunnanensis complex, as more effective purging selection reduced the accumulation of homozygous variants. We also detected signals of positive selection and adaptive introgression in different lineages, which facilitated the accumulation of favorable variants and formation of local adaptation. Hence, both types of selection and exogenous introgression could have mitigated inbreeding and facilitated survival and persistence of C. chinensis. Overall, our study provides critical insights into lineage differentiation, local adaptation, and the potential for future recovery of endangered trees.

The identification and understanding of cryptic intraspecific evolutionary units (lineages) are crucial for planning effective conservation strategies aimed at preserving genetic diversity in endangered species. However, the factors driving the evolution and maintenance of these intraspecific lineages in most endangered species remain poorly understood. In this study, we conducted resequencing of 77 individuals from 22 natural populations of Davidia involucrata, a “living fossil” dove tree endemic to central and southwest China. Our analysis revealed the presence of three distinct local lineages within this endangered species, which emerged approximately 3.09 and 0.32 million years ago. These divergence events align well with the geographic and climatic oscillations that occurred across the distributional range. Additionally, we observed frequent hybridization events between the three lineages, resulting in the formation of hybrid populations in their adjacent as well as disjunct regions. These hybridizations likely arose from climate-driven population expansion and/or long-distance gene flow. Furthermore, we identified numerous environment-correlated gene variants across the total and many other genes that exhibited signals of positive evolution during the maintenance of two major local lineages. Our findings shed light on the highly dynamic evolution underlying the remarkably similar phenotype of this endangered species. Importantly, these results not only provide guidance for the development of conservation plans but also enhance our understanding of evolutionary past for this and other endangered species with similar histories.

To explore whether there were any endangered links in sporogenesis and development of male and female gametophyte of endangered Berchemiella wilsonii， the reproductive biology of B. wilsonii was observed using paraffin section technique. The results showed that the flower of B. wilsonii had five stamens， four anthers， and the mature anther wall was composed of one inner layer， two middle layers and one tapetal layer. The tapetum developed normally with regularly arranged cells closely connected with the middle layer cells containing multiple nuclei in each cell. The cytoplasmic division of microspore mother cells was synchronous during meiosis， and mainly formed tetrahedral tetrads， the mature pollen grains were bicellular， round or oval in shape， which most of them had three germinating tubes. There were a few abnormal tapetum development and a few abortive pollen during anther development. B. wilsonii had two locule in ovary， only one chamber developed. The ovule was anatropous double integuments and crassinucellate. The chalazal end megaspore developed into functional megaspores，which underwent three times consecutive mitosis and further developed into polygonum embryo sac with seven cells and eight nucleus. Ovary ovule development was basically synchronized. The process of the mega-microsporogenesis and development of female and male gametophyte of B. wilsonii were normal， which was not the reason for the low seed setting rate.

Understanding the driving forces of speciation is a central question in evolutionary biology. Cycas bifida (Dyer) K. D. Hill and Cycas micholitzii Dyer are two morphologically similar Cycas (Cycadaceae) species with deeply pectinate megasporophylls and dichotomously divided leaflets. Geographically, they are isolated by the Red River Fault Zone (RRFZ), which acts as a biogeographical barrier for many Cycas species. In this study, we investigated the divergence, genetic diversity, genetic structure, and demographic history of C. bifida and C. micholitzii to uncover the speciation mechanisms for the two endangered species. Results revealed high historical gene flow but low contemporary gene flow between the two species, with a deep divergence occurring in the Late Miocene. The long-term geographical isolation and ecological niche differentiation were identified as important factors in driving the divergence of the two species, supported by significant isolation by distance testing, barrier analysis, and niche consistency detection. Geographical isolation by the RRFZ played a pivotal role in facilitating their divergence by constraining gene flow. Conservation genetic analyses indicated high genetic diversity within both species, coupled with disparate responses to Pleistocene climate fluctuations: C. micholitzii experienced population expansion, while C. bifida displayed a mild bottleneck effect. To ensure the protection and long-term sustainability of two threatened species, relevant conservation guidelines were proposed based on the assessment of their genetic diversity and structure. This study furnishes valuable insights into the mechanisms underpinning species divergence and delivers actionable recommendations for cycad conservation.

Clear species boundaries are crucial for plans and actions on biodiversity conservation. However, morphological similarities among allied species can result in taxonomic difficulties, thus impeding conservation efforts. In China, Cinnamomum japonicum Siebold is a well-known endangered plant, yet suffers from longstanding taxonomic issues. Here, we explicitly evaluate whether C. japonicum, C. chenii, and C. chekiangense are the same phylogenetic species on the basis of a multi-individual sampling strategy. We identified three sets of low-copy orthologous genes from 19 Lauraceae taxa for phylogenetic inferences. Both the concatenation and coalescent-based phylogenies supported that C. chenii individuals were embedded in the C. japonicum clade, indicating these two taxa are conspecific. Meanwhile, C. chekiangense accessions formed a monophyly which was not sister to C. japonicum. This result, together with the morphological differences that the leaves of C. japonicum are glabrous with a faveolate pattern of venation while those of C. chekiangense have trichomes and inevident lateral veins, led us to consider both as two distinct species. Based on 17 728 neutral single nucleotide polymorphisms (SNPs), the ADMIXTURE analysis suggested that the Chinese C. japonicum populations in Zhoushan Archipelago (=C. chenii) were genetically differentiated from the Japanese and Korean ones. Furthermore, ecological niche modeling predicted that the present distribution area of Chinese C. japonicum is likely to be unsuitable under global warming scenarios. Together with its limited distribution and genetic uniqueness, we recommend that Chinese C. japonicum deserves conservation priorities.

In order to explore the population structure and dynamic characteristics of Chunia bucklandioides in Diaoluo Mountain of Hainan， the local wild population of C. bucklandioides was taken as materials， and the concentrated distribution area of the population was set as a typical sample plot to survey， and construction of population age structure instead of space for time was designed. The current population structure and dynamic characteristics were analyzed by the dynamic quantitative analysis， survival curve drawing and survival function calculating， and the future development trend of C. bucklandioides was speculated by time sequence prediction model. The results showed that： （1）The age structure of C. bucklandioides population in Diaoluo Mountain was close to an irregular pyramid type. Dynamic quantitative analysis showed that the population was a growing population， but there was a decline trend from the age class Ⅰ to Ⅲ. The population had weak growth， poor stability， high sensitivity to external interference， and a trend towards a stable population. （2）With the increase of age class， the number of standardized survival individuals decreased， the life expectancy decreased， and the mortality and vanish rate showed an upward trend. The survival curve tended to be Deevey-Ⅱ type. （3）Survival analysis showed that the population of C. bucklandioides in Diaoluo Mountain increased in the early stage， stabilized in the middle stage， and declined in the late stage. （4） After two， four and six age classes in the future， there would be a gradually decreasing trend from I to Ⅲ age class， and slightly increasing trend from Ⅳ to Ⅶ age class. The self-renewal ability of young seedlings was insufficient， and there was a risk of population shrinkage and decline. Consequently， habitat fragmentation， small distribution range， low seed yield and insufficient young individuals might be the main factors leading to the endangerment of C. bucklandioides in Diaoluo Mountain. The results suggested to promote the rejuvenation and renewal of C. bucklandioides population by setting up small nature reserve， assisting seed germination， accelerating artificial cultivation technology research， artificially expanding population size and quantity， and strengthening basic research.

Leaf variegation, the mosaic of colors on the leaf surface, can be developed by certain plant species without external influence. Although it may be associated with a variety of functions, the stable existence of different leaf color morphs within a plant species has not been fully explained by previous studies. This study focuses on the two leaf morphs of Cypripedium forrestii, an endangered lady slipper orchid, and compares their micromorphological structure, photosynthetic potential, differentially expressed genes (DEGs), and ecological features to gain a comprehensive understanding of the underlying leaf variegation polymorphism. Our findings demonstrate that leaf variegation is not pathological and does not affect photosynthetic potential. Additionally, it significantly reduces herbivory damage. We found that the probability of herbivory and leaf area loss for variegated leaves was notably higher under drought conditions. Therefore, variegated individuals may be more adaptive under such conditions, while non-variegated ones may be more cost-effective in normal years. These results suggest that different leaf color morphs may be favored by varying environmental conditions, and leaf polymorphism may be a legacy of ancient climate and herbivore fluctuations.

Although characterization of plant interactions has become a research hotspot to assess the adaptability of endangered plants, the underlying molecular basis remains elusive. Dove tree (Davidia involucrata) seedlings were watered with distilled water (CK), leaf water extract (0.025 g mL^-1) and branch water extract (0.1 g mL^-1) from Cornus controversa, respectively. Subsequently, the morphology, biomass and gene expression levels of DiSOC1-b and DiCCoAOMT1 were analyzed. The results showed that morphological traits and biomass accumulation of D. involucrata seedlings were decreased by the addition of leaf water extracts, and increased by branch water extracts. Moreover, the gene expression level of DiSOC1-b was significantly down-regulated, while the gene expression level of DiCCoAOMT1 was significantly up-regulated in the stems and roots of D. involucrata upon treatment with leaf water extracts of C. controversa. In contrast, the gene expression level of DiSOC1-b was significantly up-regulated in the leaves and stems, while the gene expression level of DiCCoAOMT1 was significantly down-regulated in the roots of D. involucrata upon treatment with branch water extracts of C. controversa. In addition, the expression level of DiSOC1-b was positively correlated with most of morphological traits and total biomass (Pβ<β0.05), while DiCCoAOMT1 was negatively correlated with the majority of morphological traits in D. involucrata seedlings (Pβ<β0.05). Taken together, these results suggest that water extracts from the leaves and branches of the C. controversa exhibit opposite allelopathic effects and affect the expression levels of genes related to growth (DiSOC1-b) and environmental adaptability (DiCCoAOMT1) in D. involucrata seedlings.

Aim: Pinus dabeshanensis, an endemic species in the Dabieshan Mountains, has significant scientific values for studying the taxonomy, phylogenetic relationships, and distribution of the genus Pinus. Currently, the wild population of P. dabeshanensis is severely limited in natural regeneration and is critically endangered. Here, we explored the potential effects of seed predation and dispersal by animals on the regeneration of P. dabeshanensis.
Methods: First, we investigated the seed production of P. dabeshanensis by focusing all the adult trees in two 1-ha plots (n = 88). Second, by tracking the fate of 2,000 seeds, we compared the seed predation and dispersal by animals between P. dabeshanensis and three sympatric tree species. These included two dominant native species, Castanea seguinii and Quercus serrata, and an introduced species Pinus armandii that is a sister species of P. dabeshanensis, which all mainly depend on scatter-hoarding animals for seed dispersal. Third, we compared the visitation frequency of potential seed predators and dispersers between P. dabeshanensis and its sympatric species by using camera-trap surveys.
Results: The results showed that: (1) The seed production of P. dabeshanensis was low, with only 312 cones produced by 21 of the 88 adult trees surveyed, and the seed abortion rate reaching 51.89% ± 0.07% (mean ± SE). (2) A total of 146 cones were collected to assess the seed predation by birds, and 90 of them were pecked by birds which was significantly more than un-pecked cones (n = 56), with an average pecking intensity of 8.94% ± 0.55%. (3) Small rodents and ground-dwelling birds (e.g., Garrulus glandarius) were the main visitors to the seeds in the forest ground, and visitation frequency varied significantly among different tree species. Specifically, for P. dabeshanensis, birds visited the seeds more frequently (n = 77) than rodents (n = 46). (4) Seeds of C. seguinii were harvested the fastest, followed by Q. serrata and P. dabeshanensis, while P. armandii were harvested the slowest. (5) Of the 2,000 seeds released in the forest, 157 seeds were successfully dispersed, including 96 P. armandii seeds and 57 P. dabeshanensis seeds, which were significantly more than C. seguinii (3 seeds) and Q. serrata (1 seed). (6) The seed dispersal distance of C. seguinii was 13.9 ± 4.0 m (mean ± SE), followed by P. dabeshanensis (7.3 ± 0.8 m), P. armandii (3.8 ± 0.4 m) and Q. serrata (1.5 m, only one seed was successfully dispersed).
Conclusion: In conclusion, both rodents and birds are potential seed dispersers of P. dabeshanensis. Compared to sympatric tree species, P. dabeshanensis does not suffer heavy seed predation or limited seed dispersal, indicating that seed predation pressure and seed dispersal limitation do not explain the poor natural regeneration of P. dabeshanensis. In addition, our results suggest that the low seed production and high abortion rate may be important factors hindering the natural regeneration of P. dabeshanensis.

Aims: Priority assessment for natural vegetation conservation is an important foundation for formulating conservation plans and allocating conservation resources. Currently, only a single factor is often employed in the assessment of vegetation conservation, and studies on systematically combining multiple factors to assess priorities in vegetation conservation are scarce. This study therefore aims to assess the conservation priorities of natural vegetation types by integrating their threatened status and conservation values.
Methods: We assessed the conservation priorities of 104 natural formations in Yunnan Province. First, we determined the threatened status of the formations based on their declining and restricted distribution (Criteria A and B) according to the IUCN Red List of Ecosystems. We then assessed the conservation value of each formation by calculating the weighted sum of three indicators, namely endangered species richness, canopy height, and carbon storage. We finally calculated the conservation priorities of the formations by integrating the data layers of threatened status and conservation value. Based on the priority assessment results, we further classified the formations into four types.
Results: The results were as follows: (1) 66.3% of the 104 formations were characterized as vulnerable (VU), endangered (EN), or critically endangered (CR), the restricted distribution range of the formations was the key factor influencing the assessment of their threatened status. (2) 45.2% of all formations had a high or extremely high degree of conservation value, whereas 38.5% of all formations had a moderate conservation value; overall, vegetation quality was high. (3) The integrated assessment results suggest that priority conservation should focus on the 31 formations with high or extremely high conservation values characterized as threatened. Secondary priority conservation is recommended for the 26 formations with moderate conservation value and threatened status, whereas proactive conservation measures should be implemented for the 16 formations with extremely high or high conservation values but not currently threatened, and implementing general conservation for all other formations. (4) The coverage ratio of priority, secondary and proactive conservation vegetation in Yunnan’s nature reserves was 19.5%, 9.7%, and 16.9% respectively, with some conservation gaps.
Conclusion: We assessed the conservation priorities of natural vegetation by considering both threatened status and conservation value. The methods and analysis developed in this study provide vital science-based support for regional conservation planning and actions in terms of ecosystem conservation.

Viviparous reproduction is a beneficial supplement to spore reproduction of pteridophytes， which enriches the reproduction and regeneration system and affects the population genetic diversity and environmental adaptability. In this study， Cystopteris chinensis， a national key protected wild plant， was selected as materials， and morphological and anatomical methods were used， the morphological and anatomical characteristics of the gemmae with the unknown process behind the pinna were examined， and the reproductive structure and development process were revealed， and the viviparous origin and ecological adaptation mechanism of the gemmae were traced. The results showed that： （1）The gemmae and sporangium groups appeared in the middle of the last veins on the abaxial leaf pinna， but the gemmae were located in the apical pinnate lobes. The gemmae formation included three stages： initiation， expansion and maturation， the gemmae gradually grew from yellow-green globule to dark green spindle-shaped， and matured when the base turned black to form a separate layer. （2）The gemmae originated from the parenchyma cells in the extension area of the vascular bundle sheath， which continuously divided and grew to form the gemmae primordium， and gradually broke through the lower epidermis of the leaf to form spherical gemmae. With the gemmae expansion， the middle and lower cells differentiated into storage cells and vascular bundles， and the apex differentiated into growth points to form buds. （3）Few gemmae could directly sprout on the leaves to form new autotrophs. After falling to the soil for 1 week， the mature gemmae began to germinate， which grew cylindrical roots at the base， and the fist bud germinated at the top. The residual gemmae still germinated into new leaves in the second year， which were different from those produced by stem buds.

Aims Rhododendron liboense, a rare plant species endemic to limestone mountains, currently persists in extremely small populations. Despite possessing significant ornamental and scientific value, this species faces critical conservation challenges from its fragile habitat and severely limited wild populations, creating an urgent imperative for comprehensive genetic studies to inform conservation strategies.
Methods This study employed double-digest restriction-site associated DNA sequencing (ddRAD-seq) to obtain single-nucleotide polymorphisms (SNP) in 43 individuals from three distinct populations. Genetic diversity, population structure, and historical population dynamics were subsequently analyzed.
Important findings The study revealed relatively low genetic diversity in R. liboense (expected heterozygosity (H_e) = 0.139 62 ± 0.003 32, nucleotide diversity (π) = 0.157 64 ± 0.003 83) with moderate genetic differentiation between populations (genetic differentiation coefficient (F_ST) = 0.075 8). Analysis indicated that within-population variation (88.22%) exceeded between-population variation (11.78%). Structure analysis, principal component analysis, and cluster analysis classified the three populations into two distinct genetic groups. Historical population dynamics analysis demonstrated a continuous increase in effective population size since the last glacial period, likely influenced by gradual climate warming conducive to species survival. Based on these findings and the population status, we recommend establishing two management units for in situ conservation and enhancing research on artificial breeding techniques to support ex situ conservation and reintroduction efforts for R. liboense.

The recent development of genetic methods has facilitated the identification of cryptic species across different groups of organisms, including plants. However, next-generation sequencing has rarely been used to study cryptic speciation in plants, especially in bryophytes, organisms with a dominant haploid life phase. The ability to capture variation across the whole genome makes this method an effective tool for distinguishing cryptic lineages. We have focused on the genetic structure of the moss Meesia triquetra along the Alps-to-Scandinavia transect. We detected the presence of the two genetically critically different lineages of M. triquetra in Europe. These lineages overlap in both morphological characters of the gametophyte and distribution ranges. However, they considerably differ in ecological preferences to groundwater pH. While lineage 1 occupied alkaline to subneutral fens, lineage 2 occurred in fens saturated with neutral to acidic water. We consider the entities cryptic species with respect to genetic and ecological differences but the absence of morphological features necessary for determining the entities. We hypothesize that fragmentation of the ancestral population of the moss in geographically isolated refugia differing in the commonness of acidic and alkaline substrates led to consequent long-term adaptation to different environmental conditions, then drove diversification in M. triquetra.

Coniferous forests are under severe threat of the rapid anthropogenic climate warming. Abies (firs), the fourth-largest conifer genus, is a keystone component of the boreal and temperate dark-coniferous forests and harbors a remarkably large number of relict taxa. However, the uncertainty of the phylogenetic and biogeographic history of Abies significantly impedes our prediction of future dynamics and efficient conservation of firs. In this study, using 1,533 nuclear genes generated from transcriptome sequencing and a complete sampling of all widely recognized species, we have successfully reconstructed a robust phylogeny of global firs, in which four clades are strongly supported and all intersectional relationships are resolved, although phylogenetic discordance caused mainly by incomplete lineage sorting and hybridization was detected. Molecular dating and ancestral area reconstruction suggest a Northern Hemisphere high-latitude origin of Abies during the Late Cretaceous, but all extant firs diversified during the Miocene to the Pleistocene, and multiple continental and intercontinental dispersals took place in response to the late Neogene climate cooling and orogenic movements. Notably, four critically endangered firs endemic to subtropical mountains of China, including A. beshanzuensis, A. ziyuanensis, A. fanjingshanensis and A. yuanbaoshanensis from east to west, have different origins and evolutionary histories. Moreover, three hotspots of species richness, including western North America, central Japan, and the Hengduan Mountains, were identified in Abies. Elevation and precipitation, particularly precipitation of the coldest quarter, are the most significant environmental factors driving the global distribution pattern of fir species diversity. Some morphological traits are evolutionarily constrained, and those linked to elevational variation (e.g., purple cone) and cold resistance (e.g., pubescent branch and resinous bud) may have contributed to the diversification of global firs. Our study sheds new light on the spatiotemporal evolution of global firs, which will be of great help to forest management and species conservation in a warming world.

Aims Analyzing characteristics of the population and community is one of the most effective approaches to determining their endangered status. Listed as second-level endangered species, Acer miaotaiense was regarded as an extremely small population species. However, as details on the distribution and population characteristics of the species are lacking in Shennongjia area, the conservation of this species is severely constrained.

Methods This study investigated population and community characteristics of A. miaotaiense in Shennongjia area. We studied the population dynamics of the species by analyzing its age structure, static life table, and survival curve.

Important findings The results showed that: (1) there were 33 species of woody plants belonging to 15 families and 20 genera in the community, and the dominant species in the community were Juglans mandshurica, Carpinus cordata, Dipteronia sinensis and Corylus chinensis. (2) The relative importance value of A. miaotaiense was 2.23%, making it a non-dominant species in the community. (3) The distribution range of A. miaotaiense in Shennongjia was very narrow (about 1.7 hm²), and the population size was small (79 plants). (4) The proportion of young individuals of A. miaotaiense was relatively high (79.75%), indicating good regeneration. (5) The species survival curve belonged to the Deevey-II type, and the mortality rate of each age group of the population was similar. However, the mortality rate increased in the juvenile stage and peaked (62.5%) in the adult stage (12.5 cm ≤ diameter at breast height < 17.5 cm). (6) Fruiting individuals were rare, and a high percentage of seeds (58.15%) was non-viable, and resistance to external disturbance was low. In summary, the small population size, narrow distribution range, and low resistance to external disturbance are the likely factors contributing to the endangered status of A. miaotaiense in Shennongjia area. We believe that the population of A. miaotaiense in Shennongjia area is declining. Therefore, it is necessary to strengthen in situ conservation of the existing A. miaotaiense population, especially the young trees in the Shennongjia area. In the future, programs should be set up to monitor the population dynamics of the species and carry out seedling breeding for population restoration of the species.

Aims Nymphaea candida, an endangered species endemic to Xinjiang and classified as a National Class II Protected Wild Plant in China, faces a high risk of extinction, necessitating immediate conservation measures. This study aims to reveal its reproductive characteristics and explore factors associated with its endangered status from a reproductive biology perspective.
Methods This study systematically examined the flowering phenology, floral morphology, breeding system, pollination process, and seed germination characteristics of N. candida in natural populations.
Important findings The flowering period spanned from May to September, with individual flowers persisting for approximately 4 d, while stigmatic receptivity was limited to 1-2 d. Pollinators were primarily hoverflies (Syrphidae), but their visitation rates were low and further reduced by adverse weather conditions. Experimental data indicated a mixed breeding system in N. candida, predominantly outcrossing but self-compatible, with pollinator dependency for successful reproduction. Seed viability was determined to be (45.33 ± 4.29)%, yet germination rates under natural conditions were significantly lower (2.67 ± 1.63)% due to physical dormancy imposed by seed coat barriers. Reproductive limitations in N. candida arose from its floral traits, pollination challenges (e.g., limited pollinator availability and low visitation rates), and low seed viability. Environmental stressors (e.g., frequent rainfall) exacerbated pollination constraints. In unpredictable pollination environments, N. candida relied on autonomous self-pollination, which may result in inbreeding depression, thereby escalating its endangerment risk.

Aims This study aims to understand the geographical distribution of threatened species of genus Epimedium in China, and to provide the basis for resource conservation and utilization.
Methods The data of Chinese Virtual Herbarium (CVH), China National Specimen Information Infrastructure (NSII), the Royal Botanic Garden Edinburgh (E), Royal Botanic Gardens, Kew (K), Muséum National d’Histoire Naturelle (P) and Universitat Wien (WU) were used. The specimens of Herbarium of Institute of Medicinal Botany, Chinese Academy of Medical Sciences (IMD), which is not included in the sharing platform but abundant in Epimedium specimens, were also examined. At the same time, combined with our field investigations and literature review, the specimen information of 25 species and 1 variety of Epimedium in China were systematically collected to verify the specimen identification and geographical distribution, and to update the endangered status and criteria.
Important findings A total of 1 017 specimens of 428 numbers were examined, and only 666 specimens of 274 numbers (64.02%) were correctly identified. Nineteen taxa (73.08%) had found new distribution compared with the recorded of Flora of China. However, 6 species were currently known to be distributed only in the type locality. The three provinces with the highest abundance of threatened species were Sichuan (12 species), Hubei (7 species) and Guizhou (6 species and 1 variety). The endangered status or criteria of 22 taxa were suggested to be adjusted. Epimedium enshiense, E. reticulatum, E. fangii and E. parvifolium were suggested to be upgraded to Critically Endangered (CR). E. flavum, E. glandulosopilosum, E. mikinorii, E. sagittatum var. glabratum, E. truncatum and E. zhushanense were suggested to be upgraded to Endangered (EN). Epimedium simplicifolium and E. fargesii were suggested to be downgraded from Critically Endangered (CR) and Endangered (EN) to Vulnerable (VU), respectively. For another 10 species, the endangered status remained unchanged and only the criteria were adjusted. The main reasons for the endangerment of Epimedium were narrow distribution, habitat decline and population decrease. Errors in the identification of specimens of threatened species of Epimedium were prominent. Most species of this genus were distributed in narrow areas and were highly threatened. Therefore, the protection of species diversity should be paid more attention. The evaluation of endangered status and criteria is a dynamic process that requires long-term monitoring and constant updating.

Cathaya argyrophylla, a National Class I protected plant and an endemic “living fossil” species in China, has fewer than 2 500 wild individuals. Over the past 40 years, extensive research have been conducted on its biological characteristics, genetic diversity, habitat requirements, and conservation strategies. However, C. argyrophylla wild populations continue to decline, presenting a severe conservation challenge. We reviewed the research progress on C. argyrophylla, analyzing its endangered status from aspects such as growth and reproduction traits, geographical distribution, and population dynamics. Additionally, we conducted surveys of fourteen wild populations in 2023 and found that C. argyrophylla seedlings are scarce, juvenile tree mortality rate is high, and population structure indicates a declining trend. This suggests that natural regeneration of C. argyrophylla is hindered, and the current conservation measures are insufficient to reverse the decline. Although progress has been made in seedling cultivation and ex situ conservation, there is still a significant gap in protecting the species’ genetic diversity, which requires urgent attention and improvement. Future research and conservation efforts should integrate multiple disciplines and apply new technologies, particularly high-throughput sequencing for conservation genomics, to reveal the endangerment mechanisms and adaptive potential of C. argyrophylla. Additionally, integration of multi-source remote sensing technologies is necessary to monitor population dynamics and habitat changes, which could provide more accurate data to support conservation of C. argyrophylla.

Aims Pinus squamata is a critically endangered species endemic to China, restricted to Qiaojia County, Yunnan Province. It faces significant challenges such as fragile habitats and difficulties in population recovery. Fungal communities play a vital role in the population maintenance and ecological adaptation of endangered plants. However, studies on the fungal community characteristics within the roots and rhizosphere of P. squamata are currently insufficient.
Methods This study used in-situ sampling and high-throughput sequencing to analyze the fungal community structures and their geographical patterns of both wild and cultivated populations of P. squamata. Additionally, it compared the fungal community structures of Pinus squamata with those of its neighboring plant species.
Important findings (1) There are significant differences in the fungal community structures within the roots and rhizosphere between the wild and cultivated populations of P. squamata. The fungal diversity in the wild populations is lower than that of the ex-situ conserved population. (2) In the wild populations, the fungal communities differ significantly between individuals in the west-slope and east-slope populations. (3) Ectomycorrhizal (ECM) fungi, such as species from the genera Sebacina, Russula, and Xanthoconium, dominate the root systems of P. squamata. Individuals in the west-slope population, which inhabit nutrient-poor soils, exhibit greater dependence on ECM fungi. (4) Pinus squamata shares some ECM fungi with neighboring tree species, highlighting the cooperative role of mycorrhizal fungal networks in resource sharing and ecological stability. This study reveals both abiotic and biotic factors influencing the fungal communities of P. squamata. Results of this study suggest that conservation efforts should combine inoculation with ectomycorrhizal fungi and improvement of the seedling soil to restore the critical ectomycorrhizal networks, thereby promoting the vision of integrated recovery of the “pine-fungus” system.

Aims The rapid fluctuations of climate are increasingly altering the fate of species, exacerbating their vulnerability, leading to the loss of genetic diversity in many species, and even pushing some to the brink of extinction. Relict plants, having survived extreme climate changes since the Cenozoic era, carry a wealth of genetic information related to environmental adaptation. Investigating the genetic basis of their population-level environmental adaptation and their potential to cope with future climate change can provide valuable insights for biodiversity conservation.
Methods In this study, restriction site-associated DNA sequencing (RAD-seq) was performed on 122 individuals from 18 populations of Pterocarya hupehensis, which is a Cenozoic relict plant distributed around the Sichuan Basin in China. Then, the ecological adaptation and genetic vulnerability of P. hupehensis were studied by landscape genomics. First, we use a latent factor mixed model (LFMM) and Pcadapt to detect selected sites. Second, a Mantel test based on linear models, redundancy analysis (RDA), gradient forest (GF), and generalized dissimilarity modelling (GDM) were used to investigate the response patterns of genetic variation to environmental gradients. Finally, based on the risk of non-adaptedness analysis (RONA), the vulnerability of the P. hupehensis was predicted for the SSP245 and SSP585 scenarios in 2090.
Important findings A total of 398 single nucleotide polymorphism loci (SNPs) were significantly associated with the six climatic factors (isothermality, minimum temperature of coldest month, temperature annual range, mean temperature of wettest quarter, precipitation of wettest month, and precipitation seasonality). In addition, 177 of them were detected as selected SNPs. We found that precipitation seasonality was an important climatic factor affecting the genetic variation of P. hupehensis. A significant signal of isolation by environment (IBE) was detected, indicating that environmental factors account for more genetic variation than geographical factors. Under the SSP585 scenario in 2090, the genetic vulnerability of P. hupehensis was higher than that under SSP126 scenario. The precipitation seasonality has an important effect on the adaptative ability of the population in the northwest range of P. hupehensis. This study not only provides a theoretical foundation for the management and conservation strategies of vulnerable species in the face of future climate change, but also offers a new case study on how relict plants around Sichuan Basin may respond to future climate change.

To establish the rapid propagation system of tissue culture of an endangered plant Salvia petrophila， the disinfectant concentration and duration in the sterilization process， as well as the regulation of hormone types and concentrations on seed germination， the subculture and preliferation of stem segments with axillary buds at the base， induction and differentiation of callus from stem segments， rooting， hardening off and transplanting were investigated respectively. The results showed that （1） the appropriate sterilization method for S. petrophila seeds was 75% alcohol treatment for 30 s， followed by 5% sodium hypochlorite solution for 8 min， achieving a germination rate of 40.83%. （2） The appropriate medium for seed germination was MS supplemented with 1.0 mg⋅L^-1 6-BA and 0.1 mg⋅L^-1 NAA， resulting in a germination rate of 71.12%. （3） For subculture proliferation， the appropriate medium was MS with 1.0 mg⋅L^-1 6-BA and 0.1 mg⋅L^-1 NAA， yielding a proliferation coefficient of 5.5. （4） For stem segments， the appropriate callus induction medium was MS+1.0 mg⋅L^-1 6-BA+1.0 mg⋅L^-1 2，4-D， with an induction rate of 97.10%. The appropriate differentiation medium for callus induced from stem segments was MS+1.5 mg⋅L^-1 6-BA+0.1 mg⋅L^-1 NAA. （5） The appropriate basic medium for adventitious bud rooting was 1/2MS with 1.0 mg⋅L^-1 NAA， achieving a rooting coefficient of 99.11%. （6） After hardening off， the rooted seedlings of S. petrophila were transplanted into a mixed substrate of peat， perlite， and vermiculite in a volume ratio of 1∶1∶1， resulting in a survival rate of 85.5%. The results might lay a technical foundation for the species conservation and resource utilization of S. petrophila， and also provided valuable ideas for the rapid propagation techniques of other Salvia species.

In order to clarify the competitive influence of rare and endangered plant Ammopiptanthus mongolicus， this study selected the ecotone between A.mongolicus and Zygophyllum xanthoxylum， and used Hegyi single tree competition model to analyze the intraspecific and interspecific competition relationship by investigating 25 target trees of A.mongolicus. The results showed that intraspecific and interspecific competition intensity of A.mongolicus accounted for 5.09% and 94.91% of the total competition intensity（341.32）， respectively， indicating that the competition of A. mongolicus was mainly derived from interspecific competition. There were many competing tree species of A.mongolicus in the ecotone， and the competition intensity from high to low was Artemisia xerophytica， Caragana brachypoda，Z.xanthoxylum，Oxytropis aciphylla， A.mongolicus， Reaumuria trigyna， Krascheninnikovia ceratoides， Reaumuria soongarica， Potaninia mongolica， Asparagus gobicus. The relationship of the interspecific competition index and the total competition index with the crown width of A.mongolicus was approximately subject to the power function relationship， and the competition intensity decreased with the increase of crown width of target trees. When the crown width of target trees was less than 1.0 m， the competitive pressure was greater， and the obtained model could well reflect the competitive intensity of A.mongolicus.

Aims: Gymnospermium kiangnanense is a rare and endangered plant species endemic to China. Its distribution is restricted to Anhui and Zhejiang provinces, and it has been catalogued in the local registry of rare and endangered flora. However, there is relatively little research on it. Therefore, to investigate the genetic structure and elucidate the endangered mechanisms of G. kianganese, we conducted a comprehensive analysis based on its chloroplast genome, leading to evidence-based conservation recommendations.

Methods: This study assembled chloroplast genome sequences from 39 individuals across 6 populations to enhance the conservation of G. kiangnanense. Based on these chloroplast genomes, comparative genomic analyses and population genetic structure analyses were conducted to explore conservation strategies for G. kiangnanense.

Results: (1) The chloroplast genome of G. kiangnanense was highly conserved in terms of sequence composition, gene structure, and gene content, among which simple sequence repeats (SSRs) types exhibited obvious population characteristics. (2) The three non-coding regions in the chloroplast genome, namely spacer between psbZ and trnG-GCC (psbZ-trnG-GCC), spacer between trnT-UGU and trnL-UAA (trnT-UGU-trnL-UAA), and spacer between ycf1 and ndhF (ycf1-ndhF), all exhibited high variability. Meanwhile, the ndhF gene also showed high nucleotide diversity, suggesting that these regions had potential as molecular markers. (3) The chloroplast genome showed high genetic diversity and high genetic differentiation among populations. (4) Analysis of 39 chloroplast genome sequences from 6 populations identified 14 haplotypes, which were classified into 3 distinct lineages through Network and Beast analyses. (5) The variation among the populations of G. kiangnanense was significant, and it had a clear geographical structure of lineages. (6) Demographic history analysis indicated a stable population size in G. kiangnanense, with no evidence of past expansion.

Conclusion: Gymnospermium kiangnanense employs an outcrossing reproductive strategy, which not only enhances genetic variation but also mitigates inbreeding depression. Moreover, the existence of glacial refugia in eastern China during the Quaternary Ice Age offered a stable habitat for this species, thereby further promoting its population genetic diversity. Nevertheless, several factors are likely contributing to its endangered status, including low seed-setting rates, limited seed dispersal capacity, and excessive human activities. Therefore, based on the analysis of the chloroplast genome and conservation genetics of G. kiangnanense, the following conservation strategies are proposed: (1) Establish three conservation units according to distinct genetic lineages, with priority given to protecting the Fenglinxia Village population in Zhuji, Zhejiang Province, through the creation of a conservation area. (2) Implement managed bee pollination during the flowering period to enhance pollination and seed set rates. (3) Reduce population density to improve light availability for seedlings and promote their growth. (4) Complement in situ conservation with ex situ efforts by establishing artificial breeding programs in suitable botanical gardens. (5) Strengthen scientific outreach to minimize anthropogenic disturbances. (6) Promote its propagation and conservation through rational exploitation of its medicinal value in pharmaceutical development.