To clarify the basic characteristics of the complete chloroplast genome of Syringa villosa subsp. wolfii， the sequence information of chloroplast genome was analyzed by high-throughput sequencing technology， and its systematic evolution position was discussed. The results showed that：（1）The total length of the S. villosa subsp. wolfii chloroplast genome was 156 517 bp， which had a typical tetrad structure and had 131 functional genes， including 36 tRNA genes， 8 rRNA genes and 87 protein-coding genes respectively. （2）The relative synonymous codon usage（RSCU） analysis of the protein-coding region of the chloroplast genome showed that there were 31 codons with RSCU>1， of which 21 ended with A/U base； and there were 34 codons with RSCU<1， including 22 codons ending with G/C base. （3）In the chloroplast genome of S. villosa subsp. wolfii， 334 scattered repeats were detected， including 170 forward repeats and 164 palindromic repeats， and 227 SSR loci were discovered， and PCR primers were designed successfully for 226 of these loci. （4）Phylogenetic tree analysis based on the maximum likelihood method showed that S. villosa subsp. wolfii was the most closely to the S. yunnanensis. In this study， repeated sequences， IR boundaries and phylogeny of chloroplast genome of S. villosa subsp. wolfii were analyzed to provide reference data for molecular markers， phylogenetic classification， species identification and evaluation and DNA barcode development.

In order to clarify the characteristics and sequences variation of the chloroplast genomeof Yucca， a comparative genomics of the chloroplasts was performed， and a phylogenetic tree based on the chloroplast genome was constructed. The chloroplast genome of Y. treculeana was obtained by high-throughput sequencing technology， and combined with the published chloroplast genome of Yucca， the chloroplast genomes of six species of Yucca were studied by comparative genomics， including basic structure， SSR， boundary contraction and expansion， sequence variation and phylogenetic analysis respectively. The results showed that the chloroplast genome size， gene type and number of the six Yucca species were similar， and the interspecific genome structure was conserved. Several repeated sequences were detected in the chloroplast genome of Yucca， among which SSR loci were mostly composed of mononucleotide， dinucleotide and tetranucleotide， and preferred A and T bases. Three regions with high variation（psbK-psbl-trnS-GCU， rpl20-rps12 and ccsA-ndhD） were identified from the chloroplast genomes of six Yucca species according to the nucleic acid polymorphism index（π）≥0.008. The phylogenetic relationships constructed from the chloroplast genome and LSC+SSC region sequences were basically consistent， and the phylogenetic relationships among six Yucca species were confirmed， among which Y. treculeana and Y. queretaroensis were most closely related. The sequencing obtained Y. treculeana chloroplast genome， revealed the genome characteristics and sequence variation of six Yucca species， and clarified the relatedness among various species. The results could provide reference for subsequent molecular marker development and phylogenetic research.

In order to provide a basis for the conservation and utilization of Michelia wilsonii natural population， the phenotypes of fruit and seed traits of M. wilsonii were analyzed， and the variation mechanism and spatial autocorrelation was studied. M. wilsonii natural population was taken as materials， which located in Zhougong Mountain， Ya’an， 12 phenotypic traits were determined. The spatial variation characteristics of fruits and seeds of M. wilsonii were explored by using coefficient of variation and semi-variogram. The results showed that：（1）The average coefficient of variation of phenotypic fruit and seed traits was 27.59%， the variation extent of morphological traits was the least， and the variation extent of seed traits was more abundant than that of fruit. （2）The seed abortion rate and follicle abortion rate were the highest in the lower part of fruit， which were 18.32% and 38.22% respectively. The seed and follicle abortion rates were lowest in the middle part of fruit， which were 15.05% and 23.45% respectively. （3）The semi-variogram models were dominated by exponential and spherical models， presenting a distribution of aggregation. Except fruit length， seed longitudinal diameter and seed abortion rate， the other nine indexes showed medium and high spatial autocorrelation respectively. （4）The anisotropy ratios of the nine indexes were close to 1， and the spatial heterogeneity was isotropy. Therefore， the phenotypic fruit and seed traits of M. wilsonii had abundant variation in the medium scale spatial range.

Nutlet morphology and micromorphology of 27 species with four varieties of Carex sect. Paniceae were observed under scanning electron microscopy（SEM）. The results showed that：（1）The nutlet shape of all samples（beak excluded） were obovoid trigonous， with the length ranged from 1.53-3.59 mm. The nutlet length between different populations of the same species revealed stability and no significant difference exist by statistical analysis. （2）The epidermal cells were five to seven gonal， rarely four or eight， which was various within the different individuals of C. rouyana. The anticlinal wall was straight or microwave， and silica platform was flat， occasionally concave or slightly convex， with solitary central silica body but without satellite body. Whereas each epidermal cell of C. filipes var. kuzakaiensis and C. filipes var. tremula occasionally had two central silica bodies. （3）Based on the shape of epidermal cells， numbers of central silica platform， some species were distinguished from similar species， such as C. baimaensis and C. filipes， and it was also valuable to distinguish the varieties of C. filipes， ie. var. kuzakaiensis， var. oligostachys and var. tremula. （4）Sections Paniceae s.s. and Laxiflorae had a high consistency in the morphology and micromorphology of nutlets. It indicated that the morphology and micromorphology of nutlets were of great importance of taxonomic significance.

In order to explore the karyotype characteristics and evolutionary relationship of different populations of Sophora alopecuroides， the karyotype characteristics and evolutionary of six natural geographic populations distributed in Inner Mongolia， Gansu， Ningxia were analyzed respectively， and chromosome conventional slicing technology was used. The results showed that the number of chromosomes in six populations of S. alopecuroides was constant，2n=2x=36. There were two types of central centromere（m） chromosome and sub-central centromere（sm） chromosome in three populations. Chromosomes of most populations were only central centromere chromosome except for Population 3 in Wuwei， Gansu， with central centromere and sub-central centromere chromosome. The average arm ratio of chromosomes ranged from 1.19 to 1.37， the length ratio was between 1.72 and 2.19， and the karyotype asymmetry coefficient was from 54.30% to 57.17%. There were three types of karyotypes including 1A， 3A and 2B for S. alopecuroides. The karyotype asymmetry coefficient of population 3 of S. alopecuroides was the largest and the evolutionary degree was the highest， while those of population 19（Ordos， Inner Mongolia） was the smallest and the lowest. Cluster analysis showed that the six populations of S. alopecuroides were aggregated into two major branches of A and B. Branch A could be divided into two subclades of C and D. Among them， population 5（Wuwei， Gansu） and population 13（Alxa， Inner Mongolia） were clustered into subclade C， which had the closest relationship， whereas population 3 was clustered into subclade D alone， which was relatively distant with two populations from subclade C. Similarly， branch B could be further divided into subclade E and subclade F respectively. Subclade E was consisted of population 19 and population 43（Ordos， Inner Mongolia）， which had the closer relationship， while Subclade F only contained population 17（Yinchuan， Ningxia）， which had the relatively distant with two populations from subclade E. In this study， the chromosome number， karyotype characteristics and evolutionary trend of S. alopecuroides were discussed at the population level， which provided cytological evidence for further studying the system and evolution， and genetic diversity of germplasm resources of S. alopecuroides.

To clarify the genetic diversity and genetic structure of a rare and the endangered small population of Ferula fukanensis， it is the basis and prerequisite to develop effective conservation and management strategies. The genetic diversity and structure of 87 endangered plants F. fukanensis from three populations based on 10 pairs of SSR primers with good polymorphism and stable amplification were analyzed respectively. The results showed that small population of F. fukanensis had relatively high genetic diversity， the Nei’s gene diversity index（h_S） among the populations was 0.514， the total Nei’s gene diversity index（h_T） was 0.516， the observed heterozygosity（H_o） was 0.881， the expected heterozygosity（H_e） was 0.512， the Shannon information index（I） was 0.836 and the percentage of polymorphic bands（P_PB） was 100%， and the genetic differentiation degree of F. fukanensis was very low（F_st=0.007）， 95.9 % of the variation of F. fukanensis occurred within populations， and there was no significant correlation between genetic distance and geographical distance， 66.7% of the populations suffered from genetic bottlenecks. The results showed that F. fukanensis had abundant genetic variation and high evolutionary potential. Based on the current situation of this wild population， it is suggested to establish a protected area， and carry out in situ conservation and strengthen ex situ conservation measures such as introduction and artificial breeding to assist the conservation of F. fukanensis. This study can provide theoretical support for the conservation of plant resources of F. fukanensis and has important theoretical and practical significance.

Photosynthesis is a basic metabolism process for plants and provides the material basis for plant growth and development. Different environmental conditions determine the polymorphism of plant photosynthetic capacity， but the mechanisms regulating the divergence of photosynthetic capacity among different populations under the same environmental conditions remain still unknown. This study aims to reveal the divergence of photosynthetic capacity in different geographical populations of Arabidopsis thaliana in Europe under common garden conditions and the mechanisms of their gene transcriptional regulation. A comparative study of photosynthetic characteristics of 23 geographic A. thaliana（Arabidopsis） populations from different regions was conducted under common garden conditions by determining the gas exchange parameters， chlorophyll fluorescence parameters and SPAD values. In addition， the photosynthetic-related gene expressions of the typical populations with differences in photosynthetic capacity was examined using real-time quantitative PCR（RT-qPCR）. The comparative result revealed that gas exchange parameters differed significantly among geographical populations of Arabidopsis from different climatic zones in Europe. The variation range of net photosynthetic rate was 2-11 μmol·m^-2·s^-1.while chlorophyll fluorescence parameters varied to a lesser extent， the variation range was almost no more than 10%. Cluster analysis showed that the 23 Arabidopsis populations were divided into two groups， strong and weak photosynthetic ability respectively. The populations with strong photosynthetic capacity were mainly distributed in central and western Europe， and the average net photosynthetic rate was 7.37 μmol·m^-2·s^-1. The populations with weak photosynthetic capacity were mainly distributed in eastern and southern Europe with an average net photosynthetic rate of 4.46 μmol·m^-2·s^-1. Correlation analysis revealed a significant correlation between net photosynthetic rate， water use efficiency and SPAD. The results of redundancy analysis（RDA） suggested that the divergence of photosynthetic capacity in Arabidopsis might be related to environmental factors such as temperature and rainfall during the growing season in the region. RT-qPCR results showed that the expression of PSⅡ- and Rubisco-related genes were significantly higher in En-D and Stw-0， typical populations with strong photosynthetic capacity， than in Wa-1 and Per-1， typical populations with weak photosynthetic capacity， suggesting that transcriptional differences in PSⅡ and Rubisco genes could be involved in the regulation of photosynthetic capacity differentiation in populations. The results clarified that there were differences in photosynthetic capacity between geographic populations of Arabidopsis under common gardens， and such differences might be related to the environment of origin and have been inherited to future generations during long-term evolution. In contrast， the transcriptional regulation of PSⅡ and Rubisco-related genes might be involved in the differentiation of photosynthetic capacity in Arabidopsis.

The perennial fern Pteris vittata（Pteridaceae） is a hyperaccumulator of arsenic and is used for remediation of soils contaminated by heavy metals. In order to identify the characters that the P.vittata sporophyte thrives in xeromorphic rocky environments and hyperaccumulates ions， the brightfield and epifluorescence microscopy were used to investigate the anatomical structures and histochemical features of this species. The results were as follows： （1）The structure of the rhizome， adventitious roots and leaves of P. vittata sporophytes were all primary structures， the adventitious roots had an vascular bundles， endodermis with Casparian band， lignified sclerenchyma layers， cortex， rhizodermis. （2）The rhizomes had a dictyostele， endodermis， cortex， epidermis， cuticle. （3）The stipes had a single vascular bundle with a central endodermis， cortex， sclerenchyma layers， while the epidermis had a cuticle. The pinnae had bifacial mesophyll with palisade tissue and spongy tissue， the epidermis had a cuticle. （4）The surfaces of the rhizodermis and the root hairs were pectin-rich and underlain by a lignified cortex， and permeability tests using a berberine tracer showed that these structures retained large volumes of berberine. In summary， the suberized endodermis， lignified sclerenchyma layers， bifacial mesophyll， and a cuticle， all of which reflect an adaption to xeromorphic rocky environments. The result of the berberine permeability test are consistent with the hyperaccumulation of ions by P. vittata.

In order to explore the regulatory effect of exogenous hydrogen sulfide（H₂S） on the levels of organic acids and hormones in plants under saline-alkali stress， naked oats（Avena nuda） were used as materials to study the effect of spraying 50 μmol·L^-1 H₂S donor sodium hydrosulfide（NaHS） solution on the contents of organic acids and hormones in leaves and yield traits under 3.00 g·kg^-1 saline-alkali stress. The results showed that saline-alkali stress significantly increased the contents of succinic acid， butenedioic acid， malic acid， glucuronic acid and total organic acids， respectively， but significantly decreased the contents of pyroglutamic acid， jasmonoyl-isoleucine（JA-Ile）， trans-zeatin（tZ） and N⁶-（Δ²-Isopentenyl） adenine（iP） in leaves respectively. Under saline-alkali stress， spraying NaHS solution significantly increased the contents of 3-Hydroxy-3-methylglutaric acid， indole-3-acetic acid（IAA）， gibberellin A₇（GA₇）， methyl jasmonate（MJA）， iP and IAA/ABA ratio， respectively， but significantly decreased the contents of glucuronic acid， gibberellin A₃（GA₃）， gibberellin A₄（GA₄）， total gibberellins（GAs）， 1-aminocyclopropanecarboxylic acid（ACC） and ACC/ABA ratio respectively， while it had no significant effect on the contents of succinic acid， butenedioic acid， malic acid， citric acid， malonic acid， pantothenic acid， nicotinic acid， pyroglutamic acid， suberic acid， phenylpyruvic acid， total organic acids， gibberellin A₁（GA₁）， jasmonic acid（JA）， JA-Ile， abscisic acid（ABA）， tZ， trans-zeatin-riboside（tZR）， N⁶-（Δ²-isopentenyl） adenosine（iPA）， total jasmonic acids（JAs）， cytokinin（CTK） and the ratios of GAs/ABA， JAs/ABA and CTK/ABA respectively. The principal component analysis showed that spraying NaHS solution significantly increased the contents of organic acid 3-hydroxy-3-methylglutaric acid and hormones MJA， GA₇， tZ and IAA in leaves of naked oat under saline-alkali stress by 14.31%， 41.83%， 50.00%， 22.97% and 13.02%， respectively； while the contents of organic acids nicotinic acid， glucuronic acid and hormones GA₄， ACC， tZR and GA₃ were significantly decreased by 16.00%， 23.87%， 73.53%， 32.72%， 50.00% and 33.91%， respectively. In addition， the application of NaHS solution reduced the 1 000 grain weight of naked oat under saline-alkali stress by 5.91%， while spike number， boll number per spike， spike grain numbers and grain yield were increased by 2.19%， 9.70%， 61.60% and 52.83%， respectively. These results indicated that exogenous H₂S participates in the regulation of organic acid and hormone levels of naked oat under salt-alkali stress， which could enhance the ability of naked oat to adapt to salt-alkali stress.

In order to reveal the driving mechanism of competition dynamics and pattern formation in the process of arid forest restoration and succession， the competition and spatial distribution pattern of standing trees in arid forest China were studied， and a typical secondary Pinus tabuliformis forests was investigated in the Ziwuling Mountains， China， and four larger sample sites（0.25 hm² each） in different developmental stages were selected， according to the method using space instead of time， and some details of population， size， inter-tree competitions and spatial pattern of four sample sites were acquired respectively. The results showed that， in the four communities at different stages of succession， population densities of P. tabulaeformis were 1 476， 996， 800 and 648 per ha² respectively； population densities of Betula platyphylla were 48， 32， 44 and 16 per ha² respectively； and population densities of Populus davidiana were 64， 28， 24 and 12 per ha² respectively. Competition index of main tree specials decreased with succession， and showed P. tabulaeformis>B. platyphylla>P. davidiana. Quantity of small individuals（diameter at breast height from 2-15 cm） decreased obviously； but quantity of large individuals（diameter at breast height larger than 30 cm） increased. In all succession stages， the competitive intensity of P. tabulaeformis decreased with the increase of diameter. The horizontal spatial competition pattern of P. tabulaeformis showed a patchiness distribution. P. tabulaeformis clumped at the scales 0-5 m， and negative correlated with other tress specials at the scales 5-15 m. Quantity of small size Pinus individuals decreased obvious in later developmental stage. Inter-tree competition of P. tabulaeformis was stronger than other tree species， and inter-tree competition decreased in the later developmental stage. The conclusions are as follows： the size of trees are negatively correlated with the competition index； the competition index of P. tabulaeformis is higher than other species； the competition at community scales decline as development， and the quantity and range of the patches with an intense competition decline， but do not disappear yet. Competition and spatial relations are observed within the scales of 5-15 m which are larger than the average crown size of Pinus. The conditions suggest that the range of inter-tree influence could expand indirectly beyond their crown range through unknown methods， which should be further investigated.

In order to elucidate the mechanism of tapping panel dryness（TPD） and effectively control it， the ultrastructure and the expression patterns of reactive oxygen species（ROS）-related genes in barks from healthy（H） and different degrees of TPD trees were studied in this study. The results showed that with the development of TPD， aberrant mitochondrial ultrastructure changed including the loss of the matrix， swelling of cristae， and the cavitation of the inner cavity were observed in barks. The results of qRT-PCR experiments showed that the expression levels of HbPOD2 and HbPOD3 in TPD trees were higher than those in healthy trees， indicating the possibility of these genes being used as “marker” genes to monitor the tapping intensity， the stimulation intensity， and the occurrence of TPD. The gene HbCAT was also down-regulated in TPD trees， indicating that the balance between ROS generation and scavenging may be a key factor in the occurrence of TPD in rubber tree. The expressions of HbGST1， HbGST2， and HbPPO in TPD trees were higher than those in healthy trees， indicating these genes may be associated with in-situ coagulation of latex during TPD occurrence. This study reveals the changes of ultrastructure and the expression patterns of ROS-related genes in rubber tree barks during TPD occurrence. These findings may provide a new perspective for elucidating the mechanism of TPD in rubber tree， and provid theoretical guidance for developing methods for monitoring tapping intensity and stimulation intensity and for developing TPD-related “marker” genes in rubber trees.

In order to clarify the reproductive biological characteristics of Dendrobium chrysanthum， the flowering habits， the pollen vitality， the characteristics of stigma secretion， the fruit setting rate as well as the development and storage of seed were investigated. The results were listed as followed： （1）Its budding period and the emergence were 19 d， 23 d respectively. The population's flowering period was 28d， whereas the single flower span was from 10-15 d. （2）From the first day to the third day of flowering， the pollen viability was about 90% but decreased to 23.7% at the ninth day of flowering. The data of pollen viability significantly differed between at three former day and other latter time（P<0.01）， pollen viability varied from high to low level with the blooming. （3）The stigma of D. chrysanthum produced secretions from the 2nd day of flowering， and had the maximum yield at the 6th day， and stigma staining showed that the stigma receptivity was optimal at the 5-6 d of flowering， and stigma receptivity changed from weak to strong to and then to weak with the prolongation of bloom stage. （4）An artificial pollination was made at the fourth day after flowering. but no fruit was found after cross-pollination and same-flower pollination. In the field， the seedpod weight was from 2.02-4.83 g， seed length varied from 0.628-0.845 mm and its width was from 0.082-0.110 mm， and the ratio of length to width was 7.798 and the rate of embryo formation reached to 97.35%， and the seed vigor was 90.80%， and the seed vigor maintained at 73.20% at room temperature for 6 months. All results mentioned above indicated that the flowering period of D. chrysanthum was short， and the pollen vigor remained the highest after flowering， and the pollen matured earlier than stigma. There was no apomixis occurred in D. chrysanthum， and the artifical self-pollination caused sterile. Although it could bear well-developed seedpods under natural condition with a high seed vitality. Dried seeds could keep a good storage resistance under natural condition. This study confirms the biological characteristics of flowering and dichogamy of D. chrysanthum， and its breeding system belongs to self-incompatibility， and could provide the strategies for conservation of wild germplasm resources and a precise hand-pollination of D. chrysanthum.

Flavonols play important roles in plant responses to various environmental stresses and in the regulation of seed coat development. In this study， a transparent seed coat mutant was obtained through ethyl methane sulfonate（EMS） mutagenesis screening， compared with wild-type Arabidopsis thaliana（Col-0）， the mature seed color of the mutant was yellow， and its phenotypic trait was controlled by a recessive single gene. Using map-based cloning and fine-mapping technology， the mutant gene TT4（At5G13930） was mapped to BAC of MAH20 on chromosome 5， and the 1 299th base C of the TT4 was mutated to T， resulting in the 324th amino acid glycine mutated to glutamic acid. TT4（transparent testa 4） encoded a structural gene for flavonoid synthesis， chalcone synthase（CHS）， and after mutation， the seed coat was transparent and the seed color was yellow， then the mutant was named tt4-1. The phenotype of brown seed coat was restored by functional complement mutants， which further demonstrated the important role of TT4 in regulating the development of seed coat color. The tissue expression analysis of TT4 was conducted by promoter coupling GUS assay， and it was found that TT4 gene was expressed in the roots， stems， leaves of plant seedlings and flowers respectively. Physiological phenotypic analysis showed that the mutant tt4-1 seeds germinated earlier， and the seedlings had shorter taproots， as well as more lateral roots and root hairs， larger stomatal opening and higher water loss rate in mature leaves compared with the wild type. This study would lay a theoretical basis for further elaborating the function of TT4 gene.

In order to clarify the potential functions of bZIP transcription factor family members in Macadamia integrifolia under stress response， MibZIP1 was cloned from ‘Guire 1’ fruit. Combined with the analysis of transcription factor structure and expression patterns under different treatments， it was found that the full length of MibZIP1 was 1 157 bp， and the ORF was 927 bp， and encoded 308 aa，and had a typical bZIP Superfamily domain. Phylogenetic analysis showed that MibZIP1， TsbZIP60 and NnbZIP60 were closely related. The results of tissue expression analysis showed that MibZIP1 expression was the lowest in leaves of ‘Guire 1’ and the highest in branches of ‘695’. The expression of MibZIP1 was significantly up-regulated in ‘Guire 1’ leaves treated by zeatin， salicylic acid， ethephon and abscisic acid respectively， but was unchanged treated by gibberellin and hydrogen peroxide respectively. It was speculated that MibZIP1 was related to the stress tolerance of M. integrifolia， which provided theoretical guidance for the development of new cultivation and hormone regulation techniques.

To clarify the function of SPL gene in growth and development of Betula platyphylla，the BpSPL9 gene was cloned， and the expression vector of BpSPL9 was constructed by CREST technology， and the genetic transformation was carried out by Agrobacterium mediated method， and the phenotype of the transgenic lines was observed， respectively. The results showed that the transgenic lines with BpSPL9 suppressed were successfully obtained. The height of transgenic lines was significantly lower than that of non-transgenic lines， with shorter node spacing and smaller leaf area. The contents of 6-BA and IAA in transgenic lines were lower than those of the non-transgenic lines. It is speculated that BpSPL9 gene participated in plant growth and development by affecting the synthesis of auxin and cell division.

In order to reveal the mechanism of Ricinus communis response to heavy metal cadmium（Cd） stress， and screen out the resistance genes involved in Cd stress， by observing the seed germination and plant growth status， castor plants treated with water were used as controls to study their effects under three doses（300， 700 and 1 000 mg·L^-1） of Cd stress. The response mechanism is expected to provide new ideas for revealing the defense and detoxification mechanism of castor plant under in Cd stress. Using differential proteomics to analyze the network regulation mechanism of castor under Cd stress， that is， with the increase of Cd stress concentration， the castor plant blocks the absorption of heavy metal Cd by roots， improves their own antioxidant capacity， and inhibits Cd²⁺ operation. As well as the induction of programmed cell death and other detoxification processes to resist Cd stress damage； according to the results of omics analysis， a significantly different gene RcBSK7 was screened. Through functional verification in Arabidopsis， it can be seen that this gene can improve tolerance of castor plants to Cd stress. This study enhances the understanding of the diversity and complexity of castor plants under three Cd stresses， and provides a valuable theoretical basis for the identification of Cd-tolerant genes and the restoration of heavy metal pollution in the soil.

Salt stress had a critical impact on plant growth and development， including osmotic stress and ion toxicity， which seriously damaged agricultural production and food security. Under salt stress， plant related receptors were stimulated to send Ca²⁺ enter the cytoplasmic matrix through the Ca²⁺ channels opened on the cell membrane and intracellular calcium storage membrane， resulting in the increase of intracellular Ca²⁺ concentration and calcium signal. Ca²⁺， as an important second messenger， transmited signals within and between plant cells， downstream， and caused a series of physiological responses to salt stress at different growth and development stages. Calcium signals mainly included calmodulin（CaM）， calmodulin like protein（CML）， calcium dependent protein kinase（CDPK） and calcineurin B-like protein（CBL） and CBL interacting protein kinase（CIPK）， and sensed and transmited specific calcium signal information to the downstream， and activated plant physiological response to salt stress. This paper reviewed how plants perceived salt stress stimulation and the mechanism of calcium signal regulation， and looked forward to the problems should be solved in this research field.

A new peltate-leaved species of the genus Begonia（Begoniaceae）， B. holostyla， was described and illustrated by photos. The new species was similar to B. pulvinifera in its peltate leaves and black dots on fruits， but differed in its styles combined to a half（vs combined at base）， lunate stigma without a spiraled band（vs 2-cleft in a spiraled band）. Additionally， the relationship of geographical distribution and morphology with the similar species， B. pulvinifera， was discussed.

Sequence variation and gene composition of chloroplast genome could effectively reflect the phylogenetic and evolutionary relationships among plants. In this study， DNA libraries were prepared and sequenced by the Illumina HiSeq， chloroplast genomes offive species of Parnassia and allied genera were assembled respectively， and the structural characteristics， sequence genetic variation and codon preference of protein coding genes of Parnassia chloroplast genome with related species were compared and analyzed. The results showed that the chloroplast genome of Parnassia was conserved tetrad structure， and pseudogenization of several genes were found in P. palustris， but the chloroplast gene composition of other species was the same， encoding 115 genes. Compared with the relative species， the intron of rpl16 gene were lost in all species of Parnassia. The ratio of nonsynonymous/synonymous substitution rate of protein coding genes was low， and chloroplast genes might experience purification selection. Codon preference was consistent with the phylogenetic relationship shown by protein coding sequences. This study reveals that selection pressure may play an important role in the evolution of protein-coding genes in the chloroplast genome of Parnassia， which could enhance the understanding about evolution and adaptation of this genus.

The complete chloroplast genome of Rhodiola himalensis was sequenced， assembled and annotated using high-throughput sequencing technology， and R. himalensis was used as material， an endemic medical species to the Qinghai-Tibet Plateau. The results showed that the complete chloroplast genome of R. himalensis was 151 074 bp in length with a GC content of 37.8%. It had a typical tetrad structure with a long single copy region， a short single copy region and a pair of inverted repeat regions， and the sequence length of them was 82 309， 17 017 and 25 875 bp， respectively. The complete chloroplast genome encoded 130 genes， including 86 protein coding genes， 37 tRNA genes and seven rRNA genes. Based on the chloroplast genome of R. himalensis， a total of 25 513 codons was detected， among which the largest proportion of codons was Leu. In the IRa and IRb regions of R. himalensis， the gene of rps19 and ycf1 was deletion， and the gene of trnH in LSC region was contraction. And R. himalensis and R. sacra had the closest genetic relationship were also found. Besides， the variation frequency of single nucleotide polymorphism（SNP） was the highest within the SSC region. The complete chloroplast genome of R. himalensis was reported， assembled， annotated and analyzed， which could provide the theoretical basis for the study of genetic diversity and rational development and utilization of R. himalensis in the future.

The morphological description of Aster longipetiolatus C.C.Chang was inadequate in the original literature when compared with the specimen which we collected from its type locality， and there was a lack of cytological reports. The detailed morphological and cytological description of A. longipetiolatus were carried out， and the new evidences of plant taxonomical revision would be provided. The results showed that： ①There were some newly-discovered characteristics for A. longipetiolatus. For example， the receptacle was convex， phyllaries 3- or 4-seriate， ray floret staminodes， lamina pilosulose and achenes 5-ribbed； ②Its cytology evidence revealed that the chromosome number was 2n=18 and the karyotype formulae was 2n=2x=16m+2sm， belonged to the type 1A.

Orthotrichum tortifolium Lewinsky， an endemic to Bhutan， was recently first reported in China. Two specimens were collected by us in April， 2021 from Gongga Mountain Nature Reserve， Sichuan. The morphology was well consistent with the type of O. tortifolium. It was remarkably characterized by the flexuose to crisped leaves and the high basal membrane of endostome segments， which were rare in Orthotrichum. We provided detailed morphological description and photos here， and discussed its main differences from close species.

To elect excellent clones of Eucalyptus urophylla suitable for different water and nutrient conditions， 34 clones were selected as materials， and the variance analysis and genetic parameters were evaluated for growth and biomass in 18 months under different water and nutrient treatments by using a randomized complete block design. The results showed that the growth（height and diameter） and biomass（trunk， branch， root） of E. urophylla reached significant or extremely significant levels in different block， water， nutrient， water × nutrient interaction and clones， indicated that water， nutrient and clones affected the growth and biomass of each organ of E. urophylla. Under the combined treatment of water and nutrients， the growth and biomass of each organ were better under the combination of 33 and 32 treatments. The total fresh biomass in combination 32 was the largest， which increased by 135.70% compared with combination 11. There were significant positive correlations among fresh and dry in trunk， roots and leaves， and these values were above 0.90 respectively. The component variance for height， ground diameter and biomass ranged from 4.28-31 255.80， and the individual repeatability of most traits was above 0.15 that reached significant levels. ZQUB39 and ZQUC23 grew well in soil with low water and nutrient， while UD42， LDUC1 and ZQUA3 grew well in soil with high water and nutrient with 15% selection rate using BLUP predicted genotypes of E. urophylla clones. These excellent clones would be promted in the future.

To investigate the effects of fertilization on teak growth and understory vegetation diversity， the four-year-old teak Tectona grandis L. f. plantation in Guangxi was studied by randomized block design and carried out different kinds of fertilizer treatment respectively（included F1： 0.5 kg NPK complex fertilizer， 1.0 kg calcium fertilizer and 1.0 kg MgSO₄ fertilizer； F2： 1.0kg NPK complex fertilizer， 0.5 kg calcium fertilizer and 0.5 kg MgSO₄ fertilizer； F3：1.0 kg NPK complex fertilizer and 0.5 kg MgSO₄ fertilizer； F4： 1.0 kg NPK complex fertilizer； CK： no fertilization）. The results showed that fertilization significantly accelerated growth of teak tree height， diameter at breast height and volume. Compared with control， the average annual increment of H， D_BH and V increased 0.13-0.32 m， 0.17-0.26 cm and 4.35-9.63 dm³， respectively. The growth increment of F3 was the largest， and the growth rate of D_BH and V promoted significantly by 10.35% and 10.55% than CK. Understory vegetation types of young teak plantation were relatively abundant and involved 25 families， 39 genera and 42 species， among which Compositae and Gramineae were the main dominant species. There were significant distinctions in Shannon-Wiener index（H′）， Simpson index（D） and Pielou evenness index（J_sw） （P<0.05） and these indexes of F1 and F3 treatments were significantly higher than CK， but the Gleason species richness index（D_g） was no significant（P>0.05） between five treatments. The comprehensive evaluation scores of 12 indexes that included tree growth and understory were F3，F1，F4，F2，CK in turn. The rational fertilization of 4-year-old young teak plantation could promote the growth of trees and increase the richness and diversity of understory. The low-input application of 1.0 kg NPK fertilizer and 0.5 kg MgSO₄ fertilizer in young teak plantation is more beneficial to the growth and community stability.

In order to explore the flowering strategies of early spring flowering plants at low temperatures， five early spring flowering plants and five non-early spring flowering plants were collected，and the endogenous hormones and secondary metabolites between early spring flowering plants and non-early spring flowering plants were analyzed by high performance liquid chromatography-mass spectrometry and metabolomics. The results showed that the content of auxin（IAA） and zeatin（ZT） in early spring flowering plants were significantly lower than that in non-early spring flowering plants， while gibberellin（GA₃） and abscisic acid（ABA） were significantly higher than that in non-early spring flowering plants， indicated that GA₃ and ABA might play a regulatory role in promoting the flowering process of early spring plants. In the secondary metabolites， L-phenylalanine， the precursor of phenolic metabolites， was usually higher in non-early spring flowering plants than in early spring flowering plants. In addition， there were C6C1 phenolic compounds， including vanillic acid， syringic acid and protocatechuic acid； C6C3 phenolic compounds， including ferulic acid， chlorogenic acid and caffeic acid； Flavonoids， including apigenin， genistein， hesperidin， chrysin and galangin， were generally higher in non-early spring flowering plants than in early spring flowering plants. The changes of these secondary metabolites might be due to a large amount of material loss caused by the flowering process of flowering plants in early spring， which reduced the level of secondary metabolism. The results showed that endogenous plant hormones and secondary metabolites regulated the physiological process of flowering plants in early spring， and laid a foundation for further understanding the flowering process of plants under low temperatures.

Inflorescence is a key character affecting plant reproduction and plays an important role in plant taxonomy and phylogeny. The inflorescence types of Discorea nipponica are diverse， but relevant data are few available and often controversial. In order to distinguish the inflorescence types and characteristics of D. nipponica， a morphological observation combined with paraffin sectioning techniques was carried out to investigate the morphological characters， quantitative characters and development process of inflorescences of D. nipponica respectively. The results showed that the female inflorescence was an axillary spike， and had vestigial anther and pollen sac but didn’t produce pollen. The male inflorescence of D. nipponica showed different characteristics from the description of existing data. The male inflorescence was an infinite one composed of scorpion-tailed monochasium， which belonged to the mixed inflorescence with axillary or terminal buds developed， was shaped like spike. The leaves on some lateral branches of male plants degenerated， and axillary inflorescences gradually shortened towards the tip， presenting conical type with the terminal inflorescence. Male inflorescences had higher values than female ones in terms of average length， the number of florets， the density of florets， and flowering time respectively. The study showed that the male and female inflorescences of D. nipponica morphologies were consistent with the evolution from finite to infinite， exhibited relatively primitive features， which ensured the success of pollination and adaptability to the environment.

Saxifraga sect. Ciliatae Haworth belonging to Saxifraga Tourn. ex L. has highly species richness， but phylogenetic relationships within the section have not been well resolved. S. subsect. Hirculoideae Engl. is the largest subsection in sect. Ciliatae， which is mainly distributed in the Qinghai-Tibet Plateau and its surrounding areas. Based on the morphological characteristics， the subsect. of Hirculoideae was divided into three complex group， and the species attaching to the bumped vein at the leaf submarginal was classified to the S. diversifolia complex. Based on specimen inspection， the morphological and distributional data of 657 specimens from 24 species and two varieties were obtained， and 24 morphological characteristics of each specimen were used for principal component analysis and cluster analysis respectively. A total of 443 geographical distribution records was used to construct the distribution pattern of complex group. The cumulative contribution rate of the first seven principal components with an eigenvalues greater than one was low， only 67.748%. Among the characters of ‘cauline leaves petiolate’， ‘proximal median cauline leaves shape’， ‘inflorescence’， ‘proximal median cauline leaves size’， ‘sepal veins confluent at apex’， and ‘base of leaves cordate’， the contribution value of the first three principal components was large 0.6， could be used as the key characters for classification and identification of S. diversifolia complex. Based on morphological clustering and geographical distribution patterns， S. diversifolia complex could be divided into three branches： Himalayan Branch， Mountains Around Sichuan Basin Branch and Hengduan Mountains Branch（Contained a widespread species： S. egregia）， and the result was also supported by PCA.

The seed germination is an inherent property that plant adopt to environmental changes and the study of seed germination would help us to understand the population regeneration and seedling nursery. This study aimed to elucidate the type of seed dormancy and seed germination characteristics of Castanopsis sclerophylla， an important resource plant in China， the results showed that ①a very high proportion of the fruits was the seeds； ②the water absorption of the seeds was limited by the pericarp； ③seed germination was impeded by the pericarp， and seeds germinated in a wide temperature range after the pericarp removed；④the germination of seeds was difficult at15/5℃ or 20/10℃， but the germination was rapid at 25/15 ℃， 30/20 ℃ and 35/25 ℃ respectively. The results indicate that the diaspore（fruit） of C. sclerophylla had physical dormancy（PD）， Fagaceae is a new recorded family with PD and dehydration sensitivity. The results also support the hypothesis that PD is a relatively evolved trait.

According to Article 9.2 of International Code of Nomenclature for algae， fungi， and plants（Shenzhen Code）， the typographical errors in the protologues of 11 taxon names in vascular plants in China were corrected， including Ostodes kuangii Y. T. Chang， Carpinus lancilimba Hu， Santiria yunnanensis Hu， Angiopteris caudipinna Ching， Astragalus longicalyx C. C. Ni & P. C. Li， Camellia vietnamensis T. C. Huang ex Hu， Onosma waddellii f. latifolium W. T. Wang， Viola microdonta C. C. Chang， Cyclosorus scaberulus Ching， Acer chunii subsp. dimorphophyllum Fang and Miscanthus lutarioriparius L. Liu ex S. L.Chen & Renvoize. The holotypes of these names were deposited at China National Herbarium（PE）， Institute of Botany， Chinese Academy of Sciences.

In order to reveal the distribution pattern of genetic variation and haplotype geographical distribution pattern of Allium macrostemon， and to infer the refugia in the quaternary glaciation， the chloroplast gene fragments（psbA-trnH， rps16 and trnL-F） and nuclear gene fragments（ITS） of A. macrostemon in 14 regions of China were analyzed respectively. The results showed that the genetic diversity of A. macrostemon chloroplast gene（cpDNA） was lower than that of nuclear gene（nrDNA） （cpDNA：H_T=0.868； nrDNA：H_T=0.890）. The AMOVA analysis of cpDNA and nrDNA showed that the genetic variations occurred mainly among populations （cpDNA：92.84%； nrDNA：98.40%）， there was significant genetic differentiation among populations（cpDNA：N_st=0.918，G_st=0.866，F_st=0.928；nrDNA：N_st=0.984，G_st=0.855，F_st=0.984）， and had an obvious phylogeographical structure in A. macrostemon populations（N_st>G_st）. A total of 11 chloroplast and 14 nuclear haplotypes were identified in the A. macrostemon populations. The haplotype network and geographical distribution map showed that the chloroplast haplotype H3 and nuclear DNA genotype H1 had the highest frequency and were located in the center of the network structure， which might be the ancient haplotype. In addition， the glacial refuge hypothesis suggested that the region with high genetic diversity， ancient haplotype and more endemic haplotype might be the glacial refugia of A. macrostemon. Therefore， it was speculated that in the quaternary glaciation， A. macrostemon might be multiple glacial refuges in Dapanshan， Tianshui and Tonghua. The analysis could provide references for the evolution of similar herbs and enrich our understanding of the molecular phylogeography of herbaceous plants in East Asia.