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.

To explore the effects of exogenous salicylic acid（SA）added on plants， the physiological indices including membrane lipid peroxidation， reactive oxygen species accumulation， antioxidant enzyme activities， and antioxidant contents as well as gene expression in the leaves of Davidia involucrata seedlings under salt stress were investigated respectively. The results revealed that， under salt stress， the application of SA significantly reduced the relative electrolyte leakage， and inhibited the accumulation of malondialdehyde（MDA）and ROS， and increased the relative water content， activities of antioxidant enzymes（i.e.， SOD， POD， and APX）， and glutathione（GSH）contents. Moreover， treatment with SA resulted in differential expression of 2 581 genes（1 516 up-regulated and 1 065 down-regulated） under salt stress. KEGG analysis indicated that differentially expressed genes（DEGs）were enriched in nine pathways including phenylpropanoid biosynthesis. In addition， transcriptome sequencing and quantitative real-time PCR（qRT-PCR）results showed that exogenous SA significantly induced the expression of transcription factor genes including DiWRKY40， DiNAC25， DiMYB4， and DiMYB86 under salt stress. These results suggested that exogenous SA might stimulate stress responses in salt-treated D. involucrata seedlings and trigger variation in gene expression， resulting in alleviation of salt injury in D. involucrata seedlings.

Rare and endangered plants are important plant resources in nature， and play a key role in the study of plant phylogeny， ecosystem restoration， plant stress resistance physiology， and the excavation of stress-resistance genes. However， the lack of genetic information has severely restricted the conservation and utilization in most endangered plant. Due to the large genomes， complex genetic information， and unclear genetic backgrounds of endangered plants， it is relatively difficult to sequence the genomes of endangered plants. In recent years， RNA-Sequencing could directly sequence non-reference genomic species， what makes it to be widely used in the study of endangeredplants. In addition， this paper presented the prospect of the application of RNA-Sequencing technology in the study of endangered plants and suggested the new ideas of transcriptome using in the endangered plants in future.

To provide theoretical basis for genetic improvement of reproductive regulatory traits of Catalpa bungei， DELLAs family genes were identified and the function of CbuGRAS9 was analyzed. Based on the genomic data of Catalpa bungei， five CbuDELLAs genes homologous to Arabidopsis thaliana were identified and cloned. ExPASy， SWISS-MODEL， Plant-mPloc， PlantCare and other online tools were used to predict the isoelectric point， protein structure， sub-cellular localization and promoter cis-acting elements of CbuDELLAs protein. The expression differences of CbuDELLAs were analyzed by using Catalpa ‘Bairihua’ and Catalpa bungei ‘Luoqiu No.1’ as materials， and the molecular function of CbuGRAS9 was confirmed by heterologus transformation in Arabidopsis thaliana， and the proteins interacted with CbuGRAS9 were screened by yeast two-hybrid library. The results showed that the amino acid number of the five CbuDELLAs proteins ranged from 455 to 588 aa， the relative molecular weight of the proteins ranged from 5.04 to 6.43 kDa， and the isoelectric point value ranged from 4.81 to 5.14. All CbuDELLAs proteins contained DELLA and GRAS conserved domains and are hydrophilic proteins. Sub-cellular localization prediction showed that CbuDELLAs protein was located in the nucleus. The analysis of promoter cis-acting elements showed that the five promoter regions of DELLAs all contained cis-acting elements involved in gibberellin reaction. The results of qRT-PCR showed that the expression of CbuDELLAs in Catalpa ‘Bairihua’ were significantly higher than that in Catalpa bungei ‘Luoqiu No.1’， and CbuGRAS9 was the most significantly gene， and the flowering time of CbuGRAS9 transgenic plants were significantly delayed. Proteins interacted with CbuGRAS9 were mainly concentrated in metabolic pathways such as ribosome， amino acid synthesis， secondary metabolism， photosynthesis and TCA cycle.

In order to answer the controversial question of the effects of Eucalyptus introduction on plant diversity， the Eucalyptus forest in Lancang County， a large-scale introduction area of Eucalyptus in Yunnan Province， was taken as the research object， and the secondary evergreen broad-leaved forest and artificial Pinus kesiya forest were used as reference forests， and six groups of comparative plots were set up， and the plants were divided into different functional groups. The species composition characteristics and species diversity index of each functional group under Eucalyptus forest and reference forest were compared and analyzed， and the effects of Eucalyptus introduction on the species composition and diversity of understory plant functional groups were examined. The results showed that： （1）the replacement of the secondary evergreen broad-leaved forest by Eucalyptus plantation would increase the number of species in the warm-sun-medium functional group and decrease the number of species in the warm-shade-wet functional group. The replacement of artificial Simao pine forest by Eucalyptus forest would increase the number of species in warm-shade-wet functional group and reduce the number of species in warm-sun-medium functional group. （2）the species composition and important value of understory plants changed after Eucalyptus forest replaced the two reference forests， Eupatorium adenophorum occupied the absolute dominant position of warm-sun-medium functional group， and Arthraxon hispidus occupied the absolute dominant position of warm-shade-wet functional group. （3）after Eucalyptus forest replaced the two reference forests， the Shannon-Wiener diversity index and Pielou uniformity index of the warm-sun-medium functional group under the forest were significantly decreased（P<0.05）， but there was no significant effect on the species diversity index of the warm-shade-wet functional group（P>0.05）. In conclusion， Eucalyptus introduction changed the species composition of understory plant functional groups， and had different effects on the species diversity of different plant functional groups.

To investigate the role of WRKY transcription factors（TFs） in sensing saline-alkali stress signals and maintaining their tolerance function through physiological and biochemical regulatory pathways， and the WRKY42 gene of Amorpha fruticosa was cloned and the expression pattern in response to salt（NaCl） and alkali（NaHCO₃） stress and tissue organs was analyzed， and the salinity tolerance function was also studied its by overexpression in tobacco. In this study， the AfWRKY42 gene was cloned based on transcriptome sequencing data of A. fruticosa L. under stress. Bioinformatics analysis showed that AfWRKY42 contained a WRKY structural domain， two low-complexity regions and a helix region. Phylogenetic tree analysis of amino acids revealed that AfWRKY42 was most closely related to WRKY47 of Cajanus cajan and WRKY42 of Mucuna pruriens. The localization of AfWRKY42 protein in mesophyll protoplasts of Arabidopsis thaliana was confirmed in nucleus by a transient gene expression system. Quantitative analysis of AfWRKY42 gene showed the highest expression in the shoot epidermis of Sophora japonica. Detection of expression patterns in roots and leaves treated with NaCl and NaHCO₃ showed an overall increasing trend induced by it， suggesting that overall stress induced an increase in AfWRKY42 gene expression， and AfWRKY42 gene was associated with the regulation of salinity tolerance in plants. Analysis of salinity tolerance in 35S-initiated overexpressing T3 generation of tobacco lines transgenic for AfWRKY42 gene showed that the transgenic tobacco lines showed increased resistance after salinity stress treatment， it had higher chlorophyll and electrical conductivity and significantly lower malondialdehyde content than the wild type， indicating that AfWRKY42 played an important regulatory role in response to salinity stress. It would provide a WRKY transcription factor candidate gene for salinity resistance breeding and lay the foundation for improving the resistance of A. fruticosa and other plants.

Plant development is highly plastic. As ambient temperature increased， plant stems and petioles elongated， and promoted leaf surface cooling， the process known as thermomorphogenesis. High temperatures also triggered root elongation， which named as root thermomorphogenesis. There were many studies on the regulation of plant shoot thermomorphogenesis， but few investigations on the regulatory mechanisms of plant root thermomorphogenesis. In this review， we summarized the recent progresses in the field of plant root thermomorphogenesis， and proposed future research directions.

To investigate the physiological adaptability of mangrove plants under different salinity， the influences of different salinity（0， 5%， 10%， 15%， 20%， 25%， 30%， 35%） on the growth of six mangrove species（Bruguiera gymnorhiza， Ceriops tagal， Rhizophora stylosa， Bruguiera sexangula， Aegiceras corniculatum， Kandelia obovata） were assayed， and the morphological and physiological characteristics of six species were determined respectively， including the biomass， plant height increment， base diameter increment， net photosynthetic rate， chlorophyll a content， chlorophyll b content， total chlorophyll content， superoxide dismutase（SOD） activity， proline（Pro） content and malondialdehyde（MDA） content. The results showed that the 5%-20% was suitable salinity for the growth of six mangrove seedlings， and the Parmentiera cerifera had high salt tolerance. The SOD activity， Pro content and MDA content and chlorophyll content of six mangrove seedlings increased， but net photosynthetic rate and growth rate decreased under salt stress. The results showed that the photosynthesis of the six species seedlings decreased under salt stress， the photosynthetic rate increased by increasing the chlorophyll content， and the plant stress resistance might be improved by increasing the SOD activity， Pro content and MDA content in the leaves.

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.

To provide the theoretical basis for genetic improvement of Betula platyphylla， the genetic variation of the growth and wood characters of B. platyphylla half-sibling families were studied， and the excellent pulp families were selected， and 32 seven-year-old half-sibling families were measured respectively， and the growth and wood characters of each family were analyzed by ANOVA， genetic parameters were calculated and general combining ability was estimated， multiple selection methods were used to select excellent families and evaluate excellent parents. The results showed that there were significant differences （P<0.01） in growth and wood characters among families， and the family heritability was 0.71-1.00， the heritability per plant was 2.0-3.0， the coefficient of variation ranged from 5.88% to 49.84%. There was a significantly and strongly positive correlation among DBH， tree height and volume（r：0.70-0.97）， and fiber length to width ratio had a significantly and strongly positive correlation with the fiber length（r：0.69）， while it had a significantly and strongly negative correlation with the fiber width（r：-0.76）. The general combining ability was used to evaluate the excellent parents， and the general combining ability ranges of volume， basic density and fiber length were -0.001 1-0.001 0， -0.04-0.07 and -112.09-77.36， respectively. The maternal parents of A13， A12， A21 and A24 were selected as excellent parents， and three different selection methods， including Brekin multi-trait comprehensive analysis method， principal component analysis method and breeding value method， were used to select the excellent family. After comparing the advantages and disadvantages of the three methods， five excellent pulp families were selected， and the average genetic gain of volume and cellulose reached 12.97% and 3.40%， respectively. A12， A17， A23， A19， A1 were selected as the excellent pulpwood families， which provided material for further breeding of improved varieties of fast- growing B. platyphylla.

To explore the leaf color mechanism of Acer negundo ‘Aurea’， and to provide theoretical basis for the leaf color mechanism and cultivation of golden leaf plants， the golden re-green and green leaves of A. negundo ‘Aurea’ were used as materials， the leaf color parameters， pigment content and anatomy structure of three leaf types were measured and compared. The results showed that the leaf color parameters L*， a*， b* of the golden leaves were significantly higher than re-green leaves and CK（P<0.01）. The leaf color parameters of A. negundo ‘Aurea’ showed a downward trend during the process of re-greening. The chlorophyll a， chlorophyll b， total chlorophyll and， carotenoid content of the golden leaves were significantly lower than re-green leaves and CK， ω（carotenoid）/ω（total chlorophyll） was 0.64， which was significantly higher than re-green leaves and CK（P<0.01）， and pigment content of the golden leaves increased during the process of re-green. The cross-section structure of the three types leaves were different in the thickness， the ratio and arrangement of tissue. The thickness of golden leaves was 124.51 μm， which was significantly lower than that of CK（P<0.05）. The palisade tissue thickness of 31.26 μm and the palisade/spongy ratio of 0.45 in the golden leaves were significantly lower than other two types of leaves（P<0.01）， the palisade tissue and spongy tissue were arranged irregularly and disorderly， while the other two leaf types were arranged regularly and orderly； The chloroplast length and width were 3.42 μm and 1.27 μm respectively， which were significantly smaller than the re-green leaves and CK（P<0.01）， the chloroplast volume was small and incomplete， lacking thylakoid stacks. The high ω（carotenoid）/ω（total chlorophyll）， thinner palisade tissue， lower palisade/spongy ratio and lack of stacking of thylakoid in chloroplasts were the reasons for the golden color leaves of A. negundo ‘Aurea’.

Three moss species， including Ctenidium malacodes， Ulota crispula and Ulota intermedia， were reported as new records and collected from Gongga Mt. in Sichuan， and all specimens were deposited in the Herbarium， Institute of Botany， Chinese Academy of Sciences（PE）. We provided detailed morphological descriptions and photos and discuss their main differences from neighboring species. The bryophyte diversity in Gongga Mt. area is very high， which is worthy of further investigation and research.

Stems of Populus simonii×P. nigra ‘Baicheng’ in vitro plants were selected as explants and MS medium was used to establish tissue culture system by adjusting the hormone concentrations of 6-BA， NAA， TDZ and IBA. Based on the tissue culture system， the optimal concentration of kanamycin and infection time were confirmed to establish Agrobacterium tumefaciens-mediated genetic transformation system for P. simonii×P. nigra ‘Baicheng’. By using this system， the transgenic plants overexpressed a key tension wood formation regulator LBD39 （Lateral Organ Boundaries Domain） were created successfully. The results showed that the tissue culture system consisted of three stages， including adventitious bud differentiation induction （MS+ 0.5 mg·L^-1 6-BA+0.1 mg·L^-1 NAA+0.001 mg·L^-1 TDZ， shoot differentiation rate=92.6%）， stem induction （MS+0.2 mg·L^-1 6-BA+0.05 mg·L^-1 NAA， multiplication coefficient=6.5） and rooting induction （1/2 MS+0.4 mg·L^-1 IBA， rooting percentage=100%）. The optimal kanamycin concentration for genetic transformation was 30 mg·L^-1 and the optimal infection time was 20 min， and the transgenic plants were obtained successfully after 30 d of adventitious bud differentiation induction， 15-30 d of stem induction and 25 d of rooting induction with 2% transformation efficiency respectively. By using this system， five overexpressed plants of LBD39 were obtained， and the transformation efficiency was 3.3%.

To reveal the ecological adaptation mechanism of Quercus semicarpifolia in the subalpine zone of the Hengduan Mountains， the leaves and growing soil of eight plots were selected， and the C， N and P contents and their stoichiometric characteristics of leaves and growing substrate soil were measured， and the growth-limiting elements were determined. The ecological stoichiometry homeostasis model was used to determine the state of the alpine Quercus leaves. The soil C， N and P contents of the selected eight plots ranged from 38.86-70.19， 3.54-9.46 and 0.61-2.05 g∙kg^-1， with soil ω（C）∶ω（N） 5.65-16.07， ω（C）∶ω（P） 36.98-74.42 and ω（N）∶ω（P） 4.41-12.90， mean values were 9.48， 51.79 and 6.54， respectively. Leaf C， N and P contents ranged from 428.31-473.86， 21.22-31.68 and 2.21-3.68 g∙kg^-1， leaf ω（C）∶ω（N）， ω（C）∶ω（P）， and ω（N）∶ω（P） were 14.16-22.46， 121.41-215.86 and 6.99-12.84， with mean values of 17.36， 164.39 and 9.68， respectively. The alpine Quercus leaf N and P contents were higher than the global average. Leaf N and soil P， leaf N and soil ω（C）∶ω（N）， leaf ω（C）∶ω（P） and soil ω（N）∶ω（P）， leaf ω（C）∶ω（N） and soil ω（N）∶ω（P）， and leaf ω（C）∶ω（P） and leaf ω（N）∶ω（P） were highly significantly and positively correlated in each plot （P<0.01）. In addition，the leaf stoichiometric homeostasis index of alpine Quercus were probed in terms of 1/H absolute values， while 1/H_ω（N） was -0.181-0.141， 1/H_ω（P） was -1.255-1.206， and 1/H_{［ω（N）∶ω（P）］} was 0.391-0.960. The results indicated that each alpine Quercus 1/H_ω（N） was in the homeostasis state， 1/H _ω（P） and 1/H_{［ω（N）∶ω（P）］} were mostly in the weakly homeostasis state， weakly sensitive and sensitive state. Leaf ω（N）∶ω（P） ratio was less than or close to 16， illustrating that alpine Quercus in this region tended to be not deficient in both N and P elements. Alpine Quercus might overstore N and P elements to adapt to the changing external habitat， but still had a more conservative strategy for the use of external P elements. The alpine Quercus forests in this region had formed a good nutrient supply and return relationship with the soil in the long-term succession process， which had formed a relatively complete and stable subalpine forest ecosystem.

In order to investigate the effects of drought on the interspecific relationship and growth of the invasive plant Bidens pilosa and the native species Buddleja lindleyana， two methods were designed： interspecific group（one plant of each of two species were planted in a pot） and baffled group（a baffle separated the two plants in the interspecific group）， and two water treatments were applied， including the drought group （30%-35% saturated moisture content） and control group（90%-100% saturated moisture content）， and plant morphological characteristics， biomass， relative growth rate， and relative neighbor effect index of each plant feature were measured respectively. The results showed that： （1）under both drought conditions， interspecific interactions promoted the root， stem， leaf， and total biomass of Bidens pilosa， whereas water availability altered the interspecific interactions of Buddleja lindleyana， with competition under the drought treatment and facilitation under the control treatment； （2）under drought conditions， interspecific interactions increased the relative growth rate and root-to-shoot ratio of Bidens pilosa root， stem， and leaf biomass， and decreased the specific leaf area and root-to-shoot ratio of Buddleja lindleyana（P<0.05）. （3）Interspecific interactions significantly promoted the growth of root length， root surface area， and root tip number in both species（P<0.05）. The results indicate that interspecific interactions promote the growth performance of Bidens pilosa under drought conditions， provid it with a competitive advantage in arid habitats， potentially as part of its invasion strategy.

To explore the effect of tree age of ancient Platycladus orientalis on rooting of cuttings propagated from them and the physiological mechanism during the cutting process， the cuttings of 5， 100， 300 and 700 years P. orientalis female trees were used as scions respectively， and the phloem at the base of the cutting at rooting stages［0 d （S1， stage of before cutting）， 35 d（S2， stage of callus formation）， 65 d（S3， stage of adventitious root formation）， 95 d（S4， stage of adventitious root elongation）］ were harvested as the materials and the dynamic changes in the physiological indicators were measured， and the rooting rates and the numbers of rooted cuttings were counted respectively. The results showed that both of the rooting rates and the numbers of rooted cuttings propagated from ancient P. orientalis were significantly less than those of five years ones（P<0.05）. The nutrients（total sugar and total protein）， activities of antioxidative enzymes（polyphenol oxidase（PPO），peroxidase（POD）， superoxide dismutase（SOD）） and hormones（Indole-3-acetic acid（IAA）， zeatin riboside（ZR）） contents of the cuttings of five years donors were significantly more than those of ancient P. orientalis donors at all rooting stages， indicating that the high levels of these substances facilitated the rooting of the cuttings（P<0.05）. The contents of malondialdehyde（MDA）， abscisic acid（ABA）， and gibberellin（GA） showed a significant increase with increasing tree ages， indicating that the cuttings of ancient P. orientalis contained more harmful substances and hormones that inhibited rooting（P<0.05）. The nutrients（total sugar and total protein） and hormone（IAA and GA） contents showed a trend increased first and then decreased throughout the four stages， and it was worth noting that the contents reached maximum value at S3. On the contrary， ABA contents at S3 were significantly lower than that of another three stages（P<0.05）. The results indicated that the stage of adventitious root formation（S3） was a critical stage during the cutting process（P<0.05）. The larger the ratio of ω（IAA）/ω（ABA） and ω（ZR）/ω（ABA） were， the better for adventitious root formation. Tree ages significantly affected the rooting rate of P. orientalis cuttings， but there was no significant difference in the rooting rate of cuttings of ancient P. orientalis of different ages. Therefore， the reasons for difficulties in rooting of cuttings from ancient P. orientalis were mainly attributable to the lack of nutrients（total sugar and total protein）， activities of antioxidative enzymes（PPO， POD， and SOD） and endogenous hormones（IAA and ZR） beneficial to rooting.

In order to investigate the effects of saline-alkali stress on the plant growth， seedling of Heucheramicrantha ‘Silver Fan’ was used as materials， and 30， 60， 90， 120 and 150 mmol·L^-1 NaCl and NaHCO₃， and 20， 30， 40， 50 and 60 mmol·L^-1 Na₂CO₃， were used to simulate salt stress， salt alkali stress， and alkali stress， respectively. The experiment used 1/4 Hoagland nutrient solution as the control， and used water culture method to treat seedlings for 0， 7 and 14 d. The response of plants was observed from aspects such as salt damage rate and physiological indicators， and the effects of salt stress on the growth of ‘Silver Fan’ seedlings were analyzed and evaluated by principal component analysis of 7 indicators. The results showed that under different salt alkali stress treatments， the relative conductivity and malondialdehyde content（MDA） of the seedlings showed an increasing trend with time and concentration. The seedlings treated with 30 mmol·L^-1 NaCl or NaHCO₃ showed no obvious symptoms of salt damage， and all physiological indicators showed an upward trend with the prolongation of treatment time； With the increase of concentration and stress time， the salt damage index of seedlings increased， but the ornamental value decreased. The overall trend of superoxide dismutase（SOD） increased first and then decreased， reaching the maximum value at 90 mmol·L^-1 NaCl and 60 mmol·L^-1 NaHCO₃， respectively. Under the same stress time， the contents of chlorophyll（Chl）， chlorophyll a（Chla）， and chlorophyll b（Chlb） decreased continuously， while ρ（Chla）/ρ（Chlb） increased with the increase of stress concentration. Under different concentrations of Na₂CO₃ stress， the SOD activity generally showed an upward trend， reaching the maximum value at 50 mmol·L^-1， and the contents of Chl， Chla， and Chlb generally showed a downward trend. However， under the same time conditions of stress， ρ（Chla）/ρ（Chlb） decreased first and then increased with the concentration increasing， and the ratio of ρ（Chla）/ρ（Chlb） was the smallest under 40 mmol·L^-1 treatment. In general， ‘Silver Fan’ seedlings had a certain salt alkali resistance ability， and could grow at NaCl concentration<90 mmol·L^-1， NaHCO₃ concentration<60 mmol·L^-1， and Na₂CO₃ concentration< 40 mmol·L^-1， and had certain ornamental value， respectively. The results of principal component analysis showed that the relative conductivity， Chla， and Chlb contents could be used as indicators for evaluating the salt alkali resistance of the ‘Silver Fan’.

In order to explore the law of flower color change of Hibiscussyriacus during the flowering process and the influence of physical and chemical factors such as pH， metal ions and water content on its flower color， the composition and physicochemical factors of anthocyanins in the petals of H. syriacus ‘Qiansiban’ and ‘White Chiffon’ at different blossoming periods were studied respectively by the color chromato-meter， ion emission spectrometer and high performance liquid chromatography-mass spectrometry. The results showed that： （1）In terms of the composition of anthocyanins， 10 kinds of flavonoids such as Quercetin-3-glucoside， Luteolin-7-O-glucoside， and Santolol-7-O-glucoside were detected and identified in the petals of the two varieties， and 5 kinds of anthocyanins such as Mallorin-3-O-glucoside were detected and identified in the H. syriacus ‘Qiansiban’， and no anthocyanins were detected in the H. syriacus ‘White Chiffon’. （2）In the process of blossoming， the brightness of the flower color increased， the color degree decreased， and the color changed from purplish red to lavender， and light yellow to white respectively. During the blossoming， the composition of anthocyanins remained unchanged， and the content of anthocyanins and total anthocyanins gradually decreased in H. syriacus ‘Qiansiban’. （3）The pH of petals in H. syriacus ‘Qiansiban’ and ‘White Chiffon’ were both acidic， and the activities of Peroxidase（POD） and Polyphenol oxidase（PPO） showed significant difference in different periods. Among them， POD activity in H. syriacus ‘Qiansiban’ was higher than that in H. syriacus ‘White Chiffon’， while PPO activity was the opposite； calcium and magnesium ions were the highest content of metal ions in H. syriacus petals， while copper， iron， manganese， zinc and other metal ions had low content in H. syriacus petals. （4）In terms of correlation analysis， during the blossoming of H. syriacus ‘Qiansiban’， the color degree C* was significantly positively correlated with hue a*， and significantly positively correlated with calcium ion， iron ion and manganese ion respectively； during the blossoming of H. syriacus ‘White Chiffon’， the color degree C* was significantly positively correlated with hue b* and PPO activity， and negatively correlated with hue a* respectively. The research showed that the anthocyanins were the material basis of flower color change of H. syriacus flower petals. Besides anthocyanin content， the flower color change process was also closely related to the content of calcium， iron， manganese and other metal ions. PPO activity was a potential biochemical factor to promote the degradation of flavonoids in white flower varieties.

The pollen of 22 species of Saussurea and 1 species of Himalaiella were observed and compared by scanning electron microscopy to understand the degree of differentiation at the level of pollen morphology， and the pollen cluster analysis was carried out to provide a sporological basis for the classification of this genus， and further provided germplasm resources utilization of Saussurea in the region. The results showed that： （1）There were 20 species of 23 plants with subspherical pollen shape and three were oblate spherical； most of the pollen volume belonged to medium-sized pollen， and the overall type was relatively evolved. （2）Except for Saussurea Nephrolepis， which was a four-pore pollen， the pollen of the other 22 species had three pore grooves. （3）The outer wall ornamentation of pollen of 23 species could be divided into seven types： seven types of reticulate， six types of reticular and granular， six types of cavernous， and there were one smooth， one spine-based cavernous and one interspinous with wrinkled waves， one granular and one ruffled. （4）Cluster analysis based on pollen micromorphology of 23 plant species showed some consistency with the plant classification system and was even relatively clear among some subgenera. The results of this paper suggested that pollen micromorphological features might provide a basis for species identification in this genus.

In order to explore the role of WALLS ARE THIN（WAT1） in wood formation and response to stress in woody plants， bioinformatics toolswas used for analysis， and quantitative Real-time PCR（qRT-PCR） was used to investigate the expression patterns of EgrWAT1L and EgrWAT1S in different tissues， internodes and in response to different stresses， and the gene EgrWAT1S and its other transcript EgrWAT1L were cloned from Eucalyptus grandis. The results showed that the EgrWAT1S was highly expressed in phloem， while EgrWAT1L was mainly expressed in roots， and the expression patterns were significantly different under methyl jasmonate（MeJA） and salicylic acid（SA） treatment， salt stress， phosphorus（P） and boron（B） deficiency， and even opposite under MeJA and SA. These results suggested that EgrWAT1L might affect EgrWAT1S expression through transcriptional regulation and further protein translation in response to hormone and stress treatments. The studies provided a basis for further elucidate the function in the growth and development of EgrWAT1 gene and also provided a possibility for future molecular breeding of Eucalyptus.

To analyze the phenotypic traits of the floral organs of Iris lactea var. chinensis germplasm resources and to clarify the pigment composition of the petals， 22 I. lactea germplasm resources under different habitat conditions in six provinces and cities of China were used as experimental materials to systematically study the phenotypic characteristics and anthocyanin of this important ornamental part of flower organs. The phenotypic traits of the floral organs were described by RHSCC colorimetry and colorimeter colorimetry， and the mass fraction of floral pigment was determined by sodium nitrite-aluminum nitrate colorimetry and pH differential analysis， and the differences in the expression of floral pigments in different color lines were analyzed. The results showed that the flower color of 22 germplasm resources could be divided into four color families： light blue， light blue-violet， dark blue-violet and violet. The brightness（L*） of the fall and standard petals was negatively correlated with a*， positively correlated with b*， and negatively correlated with color（c*） respectively. Among the four color families， violet petals were the largest， flower branch length was the highest， and fall spot was the smallest. While light blue petals were the smallest， flower branch length was the lowest， and fall spot was the largest. It indicated that the darker the petal color， the larger the petal， and the smaller the fall spot. The mass fraction of pigment in the petals of different colors of I. lactea differed significantly. The mass fraction of carotenoid in the light blue petals was significantly higher than that in the violet color， while the mass fraction of flavonoid and anthocyanin in the violet petals were significantly higher than that in the light blue color. As the petal color deepened， the mass fraction of carotenoid decreased and the mass fraction of flavonoid and anthocyanin increased correspondingly. The correlation analysis revealed that the mass fraction of carotenoid was significantly positively correlated with fall and standard petal L*（P<0.05）， and significantly negatively correlated with fall and standard petal a* and c*（P<0.05）.The mass fraction of flavonoid was highly significantly negatively correlated（P<0.01） with fall and standard petal L* and b*， highly significantly positively correlated（P<0.01） with fall and standard petal a*， significantly positively correlated（P<0.05） with fall and standard petal c*. The correlation results between the mass fraction of anthocyanin and colorimetric parameters were similar to those of flavonoids， indicating that the mass fraction of flavonoids and anthocyanins played an important role in the coloration of I. lactea.

In order to explore the the “fertilizer island” effect in different spatial positions of two shrubs in the Gurbantunggut Desert， the dominant shrubs in the desert-Eremosparton songoricum and Calligonum mongolicum were used as research objects. Sampling points were set up by extending outward at 20（A）， 60（B）， 100（C）， and 140 cm（D） with the shrub root as the center， each sampling point was sampled at three soil depths （0<h≤5 cm， 5 cm<h≤10 cm， 10 cm<h≤20 cm， and the soil nutrient content and enrichment at different spatial locations were analyzed respectively. The results indicated that： （1）Both E. songoricum and C. mongolicum had a “fertilizer island” effect， and there were significant differences in soil nutrient content among different species and spatial locations（P<0.05）. The variation trend of the two plant soil nutrients in different spatial distributions was the same， that was， in the horizontal direction， they gradually decreased as the distance from the center of the shrub increased. Among them， the soil SOM， AK， and TN contents of E. songoricum at location D were decreased by an average of 58.16%， 52.94%， and 68.18% compared to A， respectively. The content of SOM， AK， TN， and EC in the soil at location D were decreased by an average of 61.38%， 13.33%， 69.23%， and 21.81%， respectively， compared to location A. In the vertical direction， the content of SOM， AK， and TN in the soil of the two types of plants showed the highest nutrient content in the surface soil， and showed a decreasing trend with the increase of soil depth. The content of AK， pH， and N-\mathrm{N}{\mathrm{O}}_{\mathrm{3}}^{-} in the rhizosphere soil of C. mongolicum was significantly higher than that of E. songoricum（P<0.05）. （2）The enrichment rates of SOM， AK， TN， and total phosphorus（TP） in the soil of the two shrubs showed consistent trends， that was， the enrichment rate of soil nutrients gradually decreased with the increase of soil depth， and the enrichment rate of soil nutrients gradually decreased with the increase of shrub center. （3）There was a significant correlation（P<0.05） between soil enrichment rates at different spatial locations and plant height and crown width. The plant height and crown width of E. songoricum and C. mongolicum showed a significant positive correlation with soil SOM， TN， N-\mathrm{N}{\mathrm{O}}_{\mathrm{3}}^{-} enrichment rates. In general， both plants showed a “fertilizer island effect”， with obvious spatial heterogeneity in different spatial distributions， different plants had different enrichment capacities for soil nutrients， and their “fertilizer island” effects were also different， with obvious species effects.

To explore the function roles of K⁺-efflux-antiporters KEA1 and KEA2 in Arabidopsis thaliana， wild type and kea1kea2 knock-down mutants of Arabidopsis thaliana were used as materials to investigate the effects of KEA1 and KEA2 on plant growth and development. Phenotypic analysis， propidium iodide staining to observe the structure of roots， high performance liquid chromatography to determine endogenous sugar content， transcriptome sequencing and qRT-PCR to analyze the relative expression levels of related genes， histochemical staining to detect the distribution of superoxide anion in leaves were performed respectively. The results showed that the root length of the kea1kea2 mutant was significantly shorter than that of the wild-type Col-0 plant in the absence of sucrose. Further observation showed that compared with the wild-type， the root meristem zone of kea1kea2 mutant was shorter， the endogenous sucrose content was decreased， and more O₂^·- was distributed in the leaves of the kea1kea2 mutant. However，when 30 g·L^-1 sucrose was exogenously added， there was no significant difference in root length between the wild-type and kea1kea2 mutant. Transcriptome analysis revealed that the expression of many key genes involved in sucrose signals and root growth were repressed in the kea1kea2 mutant. In summary， the results suggested that sucrose might affect AtKEA1and AtKEA2 to regulate root growth in Arabidopsis seedlings.

In order to understand the history of plant specimen collection in the Middle East Railway area in the 20th Century， the collection history of plant specimens from Heilongjiang Provincial Museum was systematically sorted out through the digital informationization， and a large number of relevant documents were consulted and analyzed. A total of 3 659 numbered plant specimens collected along the Middle Eastern Railway were sorted out， including 1 500 species of plants in 137 families and 578 genera， 20 wild plants under national key protection. The main collectors include T. P. Gordeev， V. N. Jernakov， V. S. Pokrvsky， I. V. Kozlov from the former Soviet Union， and Liu De from China. The collection covered five provinces， most of which were collected from Heilongjiang Province and the eastern part of the Inner Mongolia Autonomous Region， and a few were collected from Liaoning， Jilin and Hebei Province， 77.23% of the specimens were collected before 1949. Most families collected were Asteraceae， Poaceae and Rosaceae， accounted for 28.50% of the total plant specimens， and Artemisia， Salix， and Carex， accounted for 7.29% of the total plant specimens. Based the information， the current collated information might help to fill in the gaps in the history of plant collection in northeast China and provided reliable reference data for future research on plant classification， flora and phytogeography in northeast China and Inner Mongolia.

In order to explore the effects of nitrogen addition on the growth and non-structural carbohydrate（NSC） content of Cinnamomum bodinieri seedlings in rare earth mine tailings， one-year-old C.bodinieri cuttings were used as materials， and calcium ammonium nitrate was used as nitrogen fertilizer（containing N 15%）， and three nitrogen levels（CK（0）， N1（1.8 g per plant）， N2（3.6 g per plant）） were set up to analyze the differences in root growth， biomass distribution and NSC of C.bodinieri seedlings under three nitrogen addition levels， and to explore the response of C.bodinieri in rare earth tailings to nitrogen addition. The results showed that： Nitrogen addition increased the biomass accumulation of different tissues of C.bodinieri seedlings in rare earth tailings， and the leaf biomass and canopy biomass at N1 level were significantly increased by 44.75% and 57.43%（P<0.05）， respectively， compared with N2. Compared with CK and N1 treatment， the leaf mass ratio of N2 level was significantly increased by 123.53% and 15.85%（P<0.05）， respectively. Nitrogen addition significantly promoted the root length and root surface area of both coarse roots（diameter>2mm） and fine roots（diameter≤2mm）（P<0.05）， and the promotion effect of N1 treatment was the most significant（P<0.05）. The specific root length and specific surface area under N2 treatment were higher than those of CK and N1， and significantly different from CK（P<0.05）. For NSC， N1 treatment increased the soluble sugar mass fraction in leaves and stems， while the NSC mass fraction of fine roots under N2 treatment was significantly lower than that of CK and N1 by 46.49% and 28.61%， respectively. In summary， during vegetation restoration in rare earth mine tailings， 1.8 g per plant calcium ammonium nitrate fertilizer might be suitable for fertilization management of C.bodinieri seedlings.

Abnormal chloroplast division homozygous mutant strain parc6 and albinistic cotyledon homozygous mutant strain sco2 were identified at the DNA， RNA and cellular levels， while the effects of chloroplast abnormal division on the growth of cotyledon and leaf were investigated by adding different concentrations of sucrose to the medium and taking sl2， the double mutant with leaf abnormal division and cotyledon albino as the control. The results showed that the cotyledon of sco2 mutant was albino， while the leaf grew normally. Meanwhile， the cotyledon growth and viability of the parc6 mutant were significantly lower than the wild-type， which was equivalent to the sco2 mutant， however， the double mutant sl2 with cotyledon albinism and leaf abnormal division was severely hindered. The leaf growth and viability of the parc6 mutant were also significantly lower than that of the wild type， but recovered compared to the cotyledon. The inhibited cotyledon growth phenotype of the parc6 mutant and sco2 mutant could be confirmed by the addition of carbon source to the medium， but chloroplast fluorescence parameters of sco2 were different from the wild type. The results of BN-PAGE combined with SDS-PAGE showed that the high-level structure of the photosystem of the cotyledon and leaf were normal， indicating that chloroplasts of parc6 failed to produce enough energy to affect the growth of cotyledon and leaf. The phylogenetic analysis showed that PARC6 and SCO2 coevolved， suggesting a connection between cotyledon development and chloroplast division. Our results indicated that chloroplast size was closely related to plant growth， especially the development of cotyledon， which provided a new perspective for revealing chloroplast function.

To establish an ion exchange chromatography-pulsed amperometric detection （HPAEC-PAD） method for non-cellulosic monosaccharides in poplar（Populus spp.） cell walls， the 9 main cell wall monosaccharides could be base-line separated in one run by optimizing the separation conditions. Dionex CarbiPac^TM PA100 （4 mm×250 mm） with sodium hydroxide analytical column was used for gradient elution at flow rate is 1.0 mL·min^-1 and the column temperature of 30 ℃ was used for the determination of monosaccharide fraction in the cell wall of different poplar species. The results showed that the 9 monosaccharides had a good linear relationship in the linear range of 0.5-150.0 mg·L^-1， the correlation coefficient R² was 0.999 0-0.999 3， the reproducibility（RSD） of the method was 1.09%-3.96%， and the recovery rate by standard addition was 91.32%-109.25%. The detection limit was 1.57×10^-3-1.41×10^-2 mg·L^-1. Galacturonic acid was the highest composition followed by xylose， and the glucuronic acid content was the lowest monosaccharide. The method developed in this study was widely applicable and simple， and could be used for the detection of monosaccharides in the cell walls of poplar and other species.

In order to investigate whether there were differences in the results of leaf force-to-punch under different calibration methods and different puncture needle diameters， and the relationship between the results and leaf functional traits， 30 dicotyledonous species were selected to determine the punching force and the tearing force of the leaves and the functional traits of leaves under three puncture needle diameters of 2.0， 1.0 and 0.5 mm， respectively. The results showed that： （1）the leaf force-to-punch differed significantly（P<0.05） among the three different puncture needle diameters， for the same species when the method calibrated by perimeter， the difference between 0.5 mm and 1.0 mm was 76%， between 0.5 mm and 2.0 mm was 76%， and between 1.0 mm and 2.0 mm was 33%（P<0.05）； however， when calibrated by cross-sectional area， the difference was 66%， 56% and 30%（P<0.05） respectively. （2）There was no significant difference in leaf force to punch between the three puncture needle diameters under different calibration methods in the same life form， but there was significant differences（P<0.05） between herbs and different life form such as shrubs and trees， respectively， while the leaf force-to-punch of 0.5 mm diameter needles was greater than that of 1 and 2 mm needles. （3）Leaf force to punch was significantly positively correlated with leaf cuticle thickness， leaf thickness， and leaf tearing force（P<0.05）， and negatively correlated with specific leaf area（P<0.05）， and the correlation between punching force calibrated by needle circumference and leaf functional traits was stronger than that calibrated by cross-sectional area， whereas there was no significant difference in the correlation between leaf force to punch and leaf traits under the action of different diameters of puncture needles. Therefore， differences in both needle diameter and calibration methods produced differences in the results of leaf force to punch measurements. Differences in needle diameters did not affect the correlation between mechanical punching force and leaf functional traits， whereas differences in calibration methods affected the strength of the correlation between mechanical punching force and leaf functional traits. In conclusion， in the leaf force to punch research， selecting the appropriate calibration method and puncture needle diameter was conducive to improving the standardization and accuracy of the data， it was recommended that the two calibration methods based on the needle perimeter should be selected first， and among the three types of puncture needle diameter， 0.5 mm was selected to measure with small leaf area and dense and thin veins， and 2.0 mm was selected to measure with large leaf area and， dense and stiff veins.

To provide reference for early selection of fast-growing and adaptable varieties， the difference in growth， photosynthetic physiology， and root tip ion flux were analyzed among in five poplar varieties. The annual seedlings of Populus × euramericana ‘Bofeng 3’， P. × euramericana ‘Bofeng 1’， P. × euramericana ‘Xixiong 1’， P. × euramericana ‘Zhongxiong 7 ’， and P. deltoides × P. suaveolens cl. ‘Zhongxiong 4’ were selected as materials. Growth indexes including plant height and ground diameter were measured at 0 and 30 days under normal culture conditions， respectively. Leaf number， single leaf area， leaf length， leaf width， photosynthetic parameters including P_n， C_i， G_s， T_r， SPAD and K⁺， Ca²⁺， H⁺ ion flux of roots were measured at 10， 20 and 30 days， respectively. Under 30 days normal management， There were significant differences in plant height growth among the five varieties， from high to low， it was ‘Zhongxiong 4’， ‘Xixiong 1’， ‘Bofeng 3’， ‘Zhongxiong 7’ and ‘Bofeng 1’. Among them， the photosynthetic characteristics and transpiration rate of ‘Bofeng 1’ were the largest， and those of ‘Zhongxiong 4’ were the smallest. However， the single leaf area（（57.49±2.37） cm²）， total leaf area（（1 721.10±28.59） cm²）， net photosynthetic rate （（17 863.10± 910.21） μmol·m^-2·s^-1） and water utilization rate（（3.15±0.06）μmol·mmol^-1） of ‘Zhongxiong 4’ were significantly decreased. were the largest. The efflux velocity of K⁺ was the slowest（（62.68±0.45） pmol·cm^-2·g^-1）， and the influx velocity of Ca²⁺ was the fastest（（-74.24±1.29） pmol·cm^-2·g^-1）. The net photosynthetic rate （（8 539.70±164.64） μmol·m^-2·s^-1） and water utilization rate（（2.64±0.07） μmol·mmol^-1） of ‘Bofeng 1’ were the lowest， and the outflow velocity of K⁺ was（130.81±1.71） pmol·cm^-2·g^-1. The Ca²⁺ influx velocity（（-34.43±0.84） pmol·cm^-2·g^-1） was the slowest. In summary， among the five varieties， ‘Zhongxiong 4’ might have potential strong environmental adaptability， with the highest total leaf area， P_nand WUE， the lowest T_r， the smallest K⁺ efflux， largest Ca²⁺ influx of and most active H⁺ of root tip， and best plant height growth performance， which might be suitable for planting a wider range.

In order to explore the response strategies of plateau wetland plants to increasing temperature and CO₂ concentration， Typha orientalis， a common emergent plant in plateau areas， was selected as the research object to detect its leaf functional traits， and the simulated climatic change of increasing 2 ℃ temperature and CO₂ concentration doubling were designed by constructing a capping artificial growth chamber. The results showed that： （1）The net photosynthetic rate， stomatal conductance， intercellular CO₂ molar fraction and transpiration rate of T. orientalis under the CO₂ concentration doubling treatment were significantly reduced （P<0.05）； while the net photosynthetic rate and stomatal conductance of T. orientalis were also significantly reduced under the warming treatment（P<0.05） compared with the control group. The results indicated that the photosynthetic carbon assimilation capacity of T. orientalis was significantly reduced under the temperature increasing and CO₂ concentration doubling conditions（P<0.05）. （2）The vein density of T. orientalis leaves increased significantly under the CO₂ concentration doubling treatment； while the vein density and stomatal density increased significantly， but the vascular bundle area and catheter area decreased significantly（P<0.05） under the warming treatment compared with the control group. The results reflected the enhancement of water transport and transpiration loss capacity but the reducing of water use efficiency of T. orientalis under the conditions of warming and CO₂ concentration increasing. （3）The correlations among leaf photosynthetic parameters were looser， while the correlations between net photosynthetic rate and leaf structure traits were stronger under warming and CO₂ concentration doubling treatments than control group. The results showed that the functional synergistic or trade-off effects of leaf functional traits of T. orientalis were enhanced significantly by increasing temperature and CO₂ concentration.