To evaluate the taxonomic significance of leaf epidermal micromorphological characteristics， 11 species and one variety of simple-leaved Sorbus from sect. Aria and sect. Micromeles native to China were investigated using light microscopy（LM）and scanning electron microscopy（SEM）. The results showed that the shapes of epidermal cells wereirregular or polygonal-irregular. Anticlinal wall of polygonal cells was straight or arched， and anticlinal wall of irregular cells was arched or wavy. The area of epidermal cells varied significantly among taxa， and the size of the upper epidermal cells was larger than the lower epidermal cells. Cuticular ornaments such as ridges， striations， wrinkles， secondary thickening， thickened areas， and epicuticular waxy ornamented with crusts， granules， threads， and platelets were observed by scanning electron microscopy. Leaves were glabrous or with trichomes， and the position， color， density， and type of trichomes were important characters for the segregation of the taxa. Stomatal apparatuses were anomocytic and distributed in areole of abaxial epidermis. Guard cells had annular outer edges， with or without T-piece at stomatal pole. The cell size， length， width， area， density， and index of stomata varied significantly among taxa. Therefore， foliar epidermal micromorphology proved to be valuable for simple-leaved Sorbus taxa definition and identification.
To explore the relationship between leaf morphological characteristics and epiphyllous bud development of tropical water lilies， the viviparous and non-viviparous leaves of Nymphaea ‘Ruby’and N. ‘Blue Bird’ were used as materials， and the non-viviparous leaf of N. ‘Colorata’ was as control. The leaf morphological parameters of three cultivars were measured and compared， and the leaf anatomical structure during the leaf-rolling stage and leaf-expansion stage was observed using paraffin section. The results showed that all three cultivars had typical characteristics of tropical water lilies， the viviparous leaves of N. ‘Ruby’ and N. ‘Blue Bird’， except for the epiphyllous bud， their leaf length， leaf width， and leaf area were slightly lower than non-viviparous leaves， but there were no significant differences（P>0.05）， while the anatomical structural parameters of the leaves changed with the leaf development. Although the upper and lower epidermis， sponge tissue of the leaves of viviparous N. ‘Ruby’and N. ‘Blue Bird’ were thinner at the leaf-expansion stage， both were higher than that of non-viviparous leaves. However， the palisade tissue and the ratio of palisade to sponge increased at the leaf-expansion stage， and were lower than that of non-viviparous leaves， indicating that the development of the viviparous buds resulted in a decrease in the structural compactness of the palisade tissue， while the looseness of sponge tissue structure increased， but it was not related to the leaf thickness. The ratio of palisade to sponge and cell structure compactness of the non-viviparous variety N. ‘Colorata’ were significantly higher than those of the viviparous variety N. ‘Ruby’. In addition， the plasticity variation of each indicator was relatively high， and there was a certain correlation and an obvious co-evolution. Principal component analysis showed that the thickness of the upper and lower epidermis， spongy tissue， palisade tissue， the ratio of palisade to spongy， and the compactness and looseness of the leaf tissue structure might be regarded as the main indicators to reflect the anatomical structure characteristics of the viviparous leaves of water lilies. Viviparous leaves responded to epiphyllous bud development by changing the structure of mesophyll tissue.
In order to clarify the taxonomic value and systematic significance of leaf epidermal trichomes characters， the leaf epidermal trichomes of 33 species of Populus in China were observed and analyzed by stereomicroscope and scanning electron microscope. The results showed that Trichomes of Populus were overall non-glandular， simple， basally fixed； and all species except P. euphratica were covered with trichome in leaf epidermis， but the distribution， appearance， and length of the trichomes varied to different degrees among species. The shape of the trichomes（cylindrical to striped）， the degree of curvature（erect to curled）， the orientation relative to the surface of the leaf epidermis（ambulatory or not）， and the length of the trichomes were of taxonomic significance. Combined with the evolutionary framework provided by molecular phylogenetic studies， this study concluded that leaf epidermal indumentum characters of Populus were difficult to distinguish at the subgeneric level， the leaf trichomes within subg. Tacamahaca were similar and stable， but the length of leaf trichomes on different branches was different， however， many species could be distinguished between subg. Turanga and subg. Populus. Leaf trichomes characters could be divided into the following types after the integration of characters： glabrous， felted， sericeous， pubescent and villous.
Located in eastern Qinghai， China， the Qinghai Lake basin extends between latitudes 36°15′-38°15′N and longitudes 97°50′-101°45′E at the transition zone between the Qinghai-xizang Plateau and the Loess Plateau， the elevations ranging from 3 160-4 953 m， and the total area encompasses 29 660 km2， and the climate is typified by the alpine continental variety. There were 823 species of seed plants， distributed across 231 genera of 61 families， accounting for 23.13%， 62.89% and 38.82% of the total species， families and genera found in Qinghai respectively. The results of taxonomic analysis indicated that： （1）The density of species in every square kilometer was only 2.78， which was relatively poor compared to the numerous natural areas in the Tangut region. （2）Including the endemic plant species in China， 99.00% of the fauna was temperate， which determined that the fauna was temperate in nature. （3）There were a few woody species， few ancient and primitive groups， yet the flora with perennial herbs as the core. （4）Some of the Chinese endemic species in this region were derived from their extensive relatives， which was a concrete embodiment of the young and derived nature of the region. （5）The North China Autonomous Region and the Southwest High Mountain Region both had different degrees of influence on this region. （6）There were few endemic genera， and the endemic species were primarily aquatic plants， showing the special evolution results of the unique and Hidden domain water wet environment of Qinghai Lake. （7）The core of China’s endemic species belonged to the Gansu-Xizang-Sichuan subtype， which had the highest diversity of species. Within the subregion of plants on the Qinghai-xizang Plateau， this area belonged to the Tangut region.
To explore the potential suitable distribution and ecological adaptability of Rhodiola tangutica on the Qinghai-Xizang Plateau， based on 38 distribution sites of Rhodiola tangutica across the plateau and seven environmental factors across current and future five periods， a relationship model between the distribution of Rhodiola tangutica and environmental factors was constructed using the MaxEnt model. The potential geographical distribution patterns for the current period（1970-2000） and four future periods（2030s， 2050s， 2070s and 2090s） under the SSP245 scenario were simulated and verified. The findings revealed that： （1）Altitude（Alt） and precipitation of the driest month（Bio14） were the most important ecological factors influencing the geographical distribution of Rhodiola tangutica， contributing rates of 89.3% and 4.9%， respectively. （2）under the current climatic context， the total suitable distribution area of Rhodiola tangutica on the Qinghai-Xizang Plateau was approximately 195.21×10⁴ km²， predominantly situated in the southern and northeastern parts of Qinghai， northwestern Sichuan， and central Xizang. （3）compared with the current period， the total suitable distribution area of Rhodiola tangutica in the next four periods would not change obviously； however， the area of high suitability would increase， with a tendency of concentrated distribution to the central Qinghai-Xizang Plateau.
To understand the distribution characteristics of Amygdalus mongolica， a rare and endangered Tertiary in the Mongolian Plateau， and its response to future climatic change， climate and soil variables with 121 population distribution points of A. mongolica were selected， and the comprehensive habitat suitability model（CHS） in the R software Biomod2 modeling platform was constructed， which was used to simulate and predict suitable habitat under the current climatic condition and three different future climate scenarios（SSP1-2.6、SSP3-7.0 and SSP5-8.5） in the future（2050S and 2090S）， and the spatial and temporal evolution characteristics was analyzed， and the migration pattern of suitable habitat was explored. The results showed that the TSS of the climate suitability model （ensemble model） was >0.75， the ROC of the distribution limitation model was >0.90， which indicated that the comprehensive habitat suitability model selected in this study might accurately simulate the potential geographical distribution characteristics of A. mongolica under different climate scenarios. The suitable habitat area of A. mongolica at present was 64.00×104 km2， mainly distributed in Inner Mongolia， Gansu and Ningxia， a small number distribution in Qinghai， Xinjiang， Shaanxi， Shanxi， Hebei and other places. The suitable habitat area of A. mongolica showed a decreasing trend under three climate change scenarios（SSP1-2.6， SSP3-7.0， SSP5-8.5） in the future， and the suitable habitat area under different climate scenarios in 2090S was smaller than that in 2050S. Its suitable distribution area extended to the west and higher latitudes as a whole.
The Northeastern region of China is one of the important distribution areas of wild Ribes， and many records of the genus in this region are incomplete or even incorrect. There is an urgent need to summarize the species and distribution of the wild Ribes in this region. Field investigation on the wild Ribes in northeast China was conducted， and the Flora of China， the northeast plants search contents， and the Northeast vascular plants survey were consulted， and related papers and electronic documents and websites were reviewed respectively. The results showed that there were six subgenus and 22 species（including eight varieties） of the wild Ribes in northeast China. Heilongjiang Province had the largest number of wild Ribes， with 12 species and two varieties， Jilin Province had eight species and four varieties， Liaoning Province had five species and four varieties， and the eastern part of Inner Mongolia Autonomous Region had seven species and two varieties. The wild Ribes in the northeast China mainly distributed in the Greater Khingan Mountains， the Lesser Khingan Mountains， the Changbai Mountains， and the coast and islands of the Liaodong Peninsula； the number of species and subgenus of this genus in the northeast China was consistent in horizontal distribution. The wild Ribes in the Lesser Khingan Mountains had the largest number of species and subgenera， and was the modern distribution center of the wild Ribes in northeast China. The Ribes in the northern part of the northeast was dominated by hermaphroditic groups， while in the southern part of the Northeast Most of them were unisexual groups. This genus was distributed from low altitude（≤200 m） to high altitude（1 800-2 100 m）， and most species were concentrated at an altitude of 300-800 m. The endemic phenomenon of this genus was very obvious. There were as many as 15 species（including six variants） endemic to domestic regions， accounting for 68%. The wild Ribes in northeast China had many species， rich resources， wide distribution and huge development potential. However， its living environment was under threat. We should pay close attention to the dynamic changes of its population and distribution area in order to take measures to protect it in time.
To explore the composition and phylogenetic diversity of species， endemics， and threatened species in different geographic units of Yunnan， and to provide scientific basis for biodiversity conservation and sustainable resource utilization in Yunnan. Based on the comprehensive Yunnan monocotyledon species database， the spatial distribution pattern of monocotyledon plants in Yunnan was revealed by using species richness， weighted endemic， threatened index， phylogenetic diversity， phylogenetic endemic， and evolutionary distinctiveness and globally endangered index， respectively， and the distribution of nature reserves was integrated， and the key areas for biodiversity conservation in Yunnan was identified. The results showed that species richness of Yunnan monocotyledons was significantly（P<0.001） and positively correlated with phylogenetic diversity， weighted endemism with phylogenetic endemism， threatened index with evolutionary distinctiveness and globally endangered； northwestern， southern， and southeastern Yunnan possessed the highest diversity and endemism in terms of species composition and phylogenetic composition； and the standardized phylogenetic diversity was higher in all regions except for northwestern and southeastern Yunnan； Northwestern， southern and southeastern Yunnan were the key conservation areas for monocotyledonous plants， and effective measures to protect them would help maintain the evolutionary history and evolutionary potential of biodiversity in the region.
Protected plants usually have high utilization value or a small population size， and are the plant groups facing the highest survival threat， and are also one of the focus objects of biodiversity conservation. Based on the systematic survey of key protected wild plants in Wenshan Prefecture， the abundance and geographic distribution of them were analyzed， and the weights were determined by using four indicators， including endangerment coefficient， genetic value coefficient， protection coefficient， and utilization value coefficient， and then the integrated value of priority protection for these plants were calculated， and the different levels of priority protection to species were classified. The results showed that the387 species of wild plants were identified under priority protection in Wenshan Prefecture， including 36 species under national-level priority protection， 259 species at the second level， 24 species under priority protection at the second level in Yunnan Province， and 78 species at the third level， respectively. Orchidaceae family accounted for 38%（112 species） of the wild plants under national-level priority protection， was an important protected taxon in Wenshan Prefecture. From the horizontal distribution level， Malipo， Maguan and Xichou Counties in the south had high species richness with 228， 224， and 200 species， respectively. On the other hand， Guangnan， Qubei and Yanshan Counties in the north-central part had lower species richness with 87， 68 and 52 species， respectively. In terms of vertical distribution， the elevation range of 1 301 to 1 500 m was the most concentrated area for wild key protected plants. Therefore， biodiversity protection efforts should focus on the southern region and areas with an altitude of 1 301 to 1 500 m. The combined value of priority protection ranged from 0.372 to 0.940， resulting in 39 species classified as Class Ⅰ， 142 species as Class Ⅱ， 123 species as Class Ⅲ， and 83 species as Class Ⅳ. Eight species， including Begonia gulinqingensis， Camellia fascicularis， Horsfieldia tetratepala， Cymbidium qiubeiense， Camellia crassicolumna var. multiplex， Dysosma pleiantha and Cypripedium henryi， were not listed as threatened species in the “China Biodiversity Red List-Higher Plants Volume（2020）”， but were assessed as Class Ⅰ Priority Conservation due to their small number of distribution individuals， and significant human disturbance and high conservation value. These species should be considered urgent targets for rescue and protection.
In order to explore the potential suitable distribution area and the suitable living environment of Corydalis trachycarpa， and to provide a theoretical basis for resource utilization and protection of C. trachycarpa. Based on the existing distribution sites， climatic variables， and environmental variables of C. trachycarpa， MaxEnt modeling and ArcGIS software were used to simulate the potential distribution of C. trachycarpa in China for four periods under current climate condition（1970-2000） and Shared Socioeconomic Pathway（SSP） 245 scenario model（2021-2040， 2041-2060， 2061-2080， 2081-2100）， and environmental factors limiting its distribution were analyzed. The results showed that the most important environmental factors determining C. trachycarpa distribution were altitude（Alt， contribution rate was 60.9%）， standard deviation of temperature seasonality（bio4， contribution rate was 11.1%）， precipitation during the warmest quarter（bio18， contribution rate was 9.4%）， and the precipitation variation coefficient（bio15， contribution rate was 7.0%）. The cumulative contribution of these four factors was 88.4%. Under current climate conditions， the MaxEnt model predicted a total potential distribution area of approximately 1.7494×106 km2 for C. trachycarpa， primarily distributed in northwest Sichuan， southern Gansu， eastern Xizang， northwest Yunnan， and Qinghai within the eastern Tibetan Plateau. Compared with the current climate conditions the most， moderate and low suitable areas of C. trachycarpa under SSP 245 scenario might increase in the next four periods， showing a trend of expansion toward Yunnan， eastern Xizang， and other lower latitude regions.
The systematic position of Messerschmidia L. has been problematic which was ever moved into Tournefortia L. or Heliotropium L. Sporogenesis and gametogenesis in Messerschmidia sibirica were observed using conventional paraffin sectioning and light microscopy to provide embryological data for a better understanding of the systematic position of Messerschmidia. The results were as follows： （1）The anther was tetra-sporangiate， the primarily matured anther wall comprised four layers： the epidermis， endothecium， a middle layer and tapetum， the development of the anther wall was of the Dicotyledonous type， the tapetum with two-nucleate cells was secretary， the epidermis was persistent and the endothecium was irregularly 2- layered with fibrous thickening； （2）Microsporocyte undergone a meiotic division with a simultaneous cytokinesis resulting in a tetrahedral microspore tetrad， the mature pollen grains were 2-celled； （3）The ovule was unitegmic， anatropous and crassinucellate with a long thin micropyle and weak integument tapetum， some of the nucellar tissue was persistent at the stage of mature embryo sac； （4）The development of the embryo sac was of a Polygonum type， the shape of the mature embryo sac was fusiform with polar nuclei fused before fertilization and antipodal cells already degenerated. The embryological characters of Messerschmidia sibirica might be very similar to those of Heliotropium. Considering the stability of embryological characters within genus， the results suggested that it might be suitable to classify Messerschmidia into Heliotropium based on the molecular phylogenies.
Dipteris shenzhenensis is a critically endangered（CR） plant distributed only in Shenzhen. The phyto-community analysis of this dominant community was studied and analyzed， and the results showed that： there were 85 species， 73 genera and 49 families of vascular plants in Dipteris shenzhenensis community， the dominant species included Gordonia axillaris， Ilex memecylifolia， Cyclobalanopsis neglecta， Enkianthus quinqueflorus， Litsea rotundifolia var. oblongifolia， Dipteris shenzhenensis， Dicranopteris pedata；Plant individuals in this community decreased with the increase of tree height， showing an “Inverted J” type distribution， which was an obvious characteristic in subtropical areas. The diversity and evenness index of all life forms showed a trend of “high in the middle and low in the two ends”； The T test of the species diversity index of different communities in the same area proved that there was no significant difference in diversity level between different communities， which belonged to the stable stage of ecological succession； Niche analysis revealed the survival status of Dipteris shenzhenensis in the community， indicating that this species was not widespread， demanding for environment and poor competitiveness in resources， and there was a risk of extinction during community succession； Interspecific association analysis revealed the interspecific relationship between this species and other dominant herbs， and identified possible complementary and competitive plants.
To explore the effects of multi-walled carbon nanotubes in gametophyte development and sporophyte production of Ceratopteris thalictroides， and to lay a foundation for conservation and breeding of endangered ferns.C. thalictroides was used as material， and five treatment group of 0（the control）， 0.5， 1.0， 2.5， 5.0 mg·L-1 was set，and the effects of different mass concentrations of multi-walled carbon nanotubes on gametophyte development and sporophyte formation of C. thalictroides were observed by light microscope. The results showed that compared with the control group， 0.5-2.5 mg·L-1 multi-walled carbon nanotube treatment could advance spore germination by about 15 d， among them， 0.5 mg·L-1 multi-walled carbon nanotubes had the best effect on spore germination， 0.5-1.5 mg·L-1 multi-walled carbon nanotubes had the best effect on protonema and plate formation， and 2.5 mg·L-1 multi-walled carbon nanotubes had the best effect on prothallus and sporophyte formation. High mass concentration （5.0 mg·L-1） of multi-walled carbon nanotubes led to deformity of some gametophytes， and spermogonium degradation， chlorosis of chloroplasts in cells， and chlorosis of chloroplasts in some cells on the developing sporophytes cells. In addition， male gametophytes was promoted by the addition of multi-walled carbon nanotube. In conclusion，0.5-2.5 mg·L-1 multi-walled carbon nanotube treatment might significantly promote gametophyte development and sporophyte production of C. thalictroides， and the number of spermogonium increased significantly， and both monoecious and dioecious gametophytes appeared simultaneously， high mass concentration of multi-walled carbon nanotube treatment might result in‘high concentration inhibition’ of gametophyte development of C. thalictroides. In the process of practical application， the corresponding addition amount should be selected based on the specific need.
Since its establishment in 2002， no taxonomic study on the genus Eurhynchiastrum Ignatov & Huttunen has been carried out in China. Based on the related specimens and literatures， the authors conducted an investigation on the genus in China. The results showed that the genus was distributed in China with a single species， E.pulchellum（Hedw.） Ignatov & Huttunen. The morphological characters， habitats and geographical distribution of the species were described. Additionally， a plate illustrating the main morphological features was provided， and a discussion on the comparison among allied genera and species was included. Furthermore， the potential geographic distribution of E.pulchellum in China was predicted.
