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

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

To investigate the anatomical characteristics of female flowers and the changes of cell wall components of Castanea mollissima during the growth and development， ‘Yanshan Hongli’ was used as materials， and the internal morphological changes were observed by paraffin sections and the changes of cell wall components were observed by fluorescence staining. According to its internal microstructure changes， the collected samples were determined at the four most important development stages： flower primordium differentiation stage， stigma primordium differentiation stage， stigma elongation stage and flowering stage. The results showed that the fluorescence intensity of cellulose in the cell wall of female flowers gradually increased during the development. Especially during the process of stigma elongation， the fluorescence intensity of cellulose in stigma and ovary was significantly enhanced. In addition， the fluorescence intensity of esterified pectin was always higher than that of acidic pectin during the four development stages and the fluorescence intensity of pectin in stigma and ovary was stronger than that of other parts. These results revealed the changes of cell wall components during the growth and development of chestnut female flowers， and provided important clues for further understanding the mechanism of chestnut growth and development.

To reveal the reproductive characteristics and pollination mechanisms of Bulbophyllum andersonii， the pollination biology including flowering phenology， breeding system， pollinator， flower morphological characteristics， and flower volatile components were investigated in a wild population in Xishuangbanna， Yunnan in 2023. The results were as follows： the blooming period of B. andersonii was in mid-July， and the individual flowering period was five days. The breeding system was outcrossing and dependent on pollinators， and the natural seed setting rate was 26.06%. Bagging experiments indicated self-incompatibility， no apomixis and no spontaneous autogamy. Floral features such as the hinge structure of the labellum， pollination channels， and broad lateral sepals played important roles in pollination. Gampsocera sp.（Chloropidae） was the only effective pollinator and exhibited lip-licking behavior during the flower visit. Using Scanning Electron Microscopy， a large number of special particles were observed on the lips of B. andersonii， which might be the food rewards for the flower visitors. Flower volatile odors primarily contained monoterpenoids and aromatics， among which 1，2-Dimethoxybenzene and N， N-diethyl-m-toluamide might be related to the flower visiting behavior of insects. The results indicated that the flower morphology and flower scent of B. andersonii were adaptable to pollination by Gampsocera sp.， which seemed to be apt to a specialized pollination system.

Establishing the somatic embryogenesis system of Isodon rubescens to give full play to its value in traditional Chinese medicine， and promote the stability and utilization of its resources. The leaves of I. rubescens were used as explants to dedifferentiate into embryonic callus and further proliferate to induce somatic embryo. The histological and cytological observation of embryonic callus and somatic embryo at each stage was made by paraffin section， and the effect of hormones on plant regeneration was tested. The results showed that in B5+1.0 mg·L^-1 2，4-D medium， leaves could dedifferentiate into light yellow and granular embryonic callus. In MS+1.0 mg·L^-1 2，4-D+0.2 mg·L^-1 6-BA medium， the embryogenic callus had the best proliferation effect， and the maximum net proliferation was 2.81 g. The optimal medium for somatic embryo induction was MS+1.5 mg·L^-1 TDZ+0.2 mg·L^-1 NAA， and the highest induction rate was 91.33%. In MS+0.5 mg·L^-1 6-BA+0.5 mg·L^-1 IBA medium， embryogenic callus containing somatic embryos could differentiate into small plants. In histological observation， the embryonic callus was yellowish or yellowish white granules with large and obvious nuclei. Two kinds of somatic embryogenesis were observed in the inner and outer origin of the callus， and the later developed into spherical， heart-shaped， torpedo-shaped， cotyledon-shaped embryo or cluster embryo structures containing starch granules. This study successfully established the indirect somatic embryogenesis system of I. rubescens， which laid a foundation for optimizing the “quality” and “quantity” of embryogenic callus， and also provided the theoretical basis for the research of molecular breeding and somatic embryo technology.

To explore a simple and suitable method for inducing meristematic nodules in multiple cultivars， the petioles of inter-subsectional and inter-sectional distant hybrid tree peony were used as explants， and the conditions for the differentiation of meristematic nodules into adventitious shoot in some cultivars were also identified. The results showed that meristematic nodules were induced by one step in 10 cultivars with 52.08%- 83.33% induction rates， the thin layers of petioles of 11 cultivars were continuously cultured on SH medium containing 0.5 mg·L^-1 NAA+1.0 mg·L^-1 CPPU+0.5（or 0） mg·L^-1 TDZ for 60-100 d in the dark， and meristematic nodules induced by one step were generated indirectly from the callus. Adventitious shoot differentiation rate of three cultivars was 6.67%-33.33% when meristem nodules were added to the modified WPM medium containing 0.5（or 1） mg·L^-1 CPPU+0.5 mg·L^-1 TDZ under light condition and sub-cultured every 15 days. Lower concentrations of CPPU and TDZ together promoted adventitious shoot differentiation， but high concentrations of CPPU alone were not conductive to adventitious shoot differentiation. The general medium for one-step induction of meristematic nodules was screened， and adventitious shoot differentiation was achieved in some cultivars， which provided an important reference for the establishment of plant regeneration system for distant hybrid tree peonies.

Seeds of 18 F. mandshurica clones were used as materials， the germination performances of clones at suitable temperatures after different stratification treatments were compared， and the relationships between germination performances and seed embryo growth changes were analyzed. The results showed that the germination performances of seeds were different among F. mandshurica clones after different stratification treatments. Seed dormancy of clones 1， 2 and 6 was shallow and could be broken after variable temperature stratification treatments for a short time（a total 18 weeks）， which the germination rate of clones 2 and 6 reached more than 75%. Seed dormancy of clones 13， 14， 15 and 16 were broken by 20-week stratification treatment （cold temperature extended for two weeks）， and clones 4， 8， 11 and 12 by 20-week stratification treatment （warm temperature extended for two weeks）. Seeds dormancy of clones 5 and 18 was deep-degree， it could be broken by extending the stratification（warm and cold temperature） time to 22 weeks. Seed dormancy of clones 3， 7， 9， 10 and 17 could be broken by stratification treatment for 20 weeks， without significant difference in the dormancy between seeds treated by extending warm and cold stratification time. The changes of embryo length， embryo rate and embryo mass ratio in the process of stratification were different in different clones， and relative extension time（two weeks） of cold temperature stratification in clones 6， 7 and 11 was conducive to embryo growth， and extension time（two weeks） of warm temperature stratification in clones 2， 5 and 17 was conducive to embryo growth. Differences in seed dormancy of different clones could not be accurately judged by changes in seed embryo growth during the stratification process， which should be judged mainly by the germination performances. The results could provide a reference for the selection of mother clones with shallow seed dormancy in production practice.

To address the problem of the rooting ability of Fraxinus mandshurica cuttings significantly decreasing after three years due to age effect， four-year-old F. mandshurica seedlings were used to investigate the role of cycle rejuvenation through cuttings in overcoming age effect in this study. The impact of the number of cycles and topping treatment on the sprouting， growth， and rooting of F. mandshurica cuttings， as well as the physiological changes during its rejuvenation process were examined. The results showed that the measurement of increasing the number of rejuvenation cycles and topping treatment both enhanced the degree of rejuvenation in F. mandshurica， which were characterized by an increased number of sprouted branches， finer branches， and shorter internodes， while significantly improved the regeneration ability of the cuttings. When the number of rejuvenation cycles reached three and was combined with topping treatment， the number of sprouted branches increased by 6.56 times， and the rooting rate increased by 7.44 times compared to non-rejuvenated treatment. During one to three rejuvenation cycles， the indole acetic acid（IAA） and cytokinin（CTK） levels in the plants increased， the gibberellin（GA₃） levels significantly increased only at the third cycle， and the abscisic acid （ABA） levels decreased gradually. After rejuvenation， the activities of catalase（CAT）， peroxidase（POD）， and superoxide dismutase（SOD） and the contents of malondialdehyde（MDA） and soluble sugars decreased in the regenerated plants. These physiological changes were consistent with the juvenile state of the plants. Cycle rejuvenation can effectively restore the juvenile state， induce the formation of sprouts with higher IAA and GA₃ levels and lower ABA levels， and simultaneously reduce the oxidative state and soluble sugar content in F. mandshurica. These changes are beneficial for achieving rejuvenation of F. mandshurica， thereby increasing the rooting rate of F. mandshurica cuttings and enabling rapid and efficient clonal propagation of superior F. mandshurica varieties.

Exploring the coupling relationship among stand structure， site conditions， protection intensity， and plant diversity is helpful to improve the effect of plant diversity protection in protected areas. Based on this， the forest community of the Chuona River National Nature Reserve in Daxing’anling Mts was selected as the research object， the plant diversity and stand structure characteristics of the arbor， shrub， and herb layers were investigated， and the soil samples were collected and the soil physicochemical properties were determined. The frequency distribution， redundancy ranking and variance analysis were used to reveal the characteristics of plant diversity and its coupling relationship with influencing factors. The results showed that：（1）Larix gmelinii was the dominant tree species in the tree layer of Chuona River Reserve， with a relative abundance of 64.35%， followed by Betula platyphylla. The proportion of lingonberry（Vaccinium vitis-idaea） in shrubs was the highest， reaching 72.70%. A total of 77 herbs were recorded， of which Carex callitrichos accounted for the largest proportion（23.72%）. （2）The order of richness index and diversity index was herb layer>arbor layer>shrub layer， and the shrub layer had the highest evenness index. （3）Redundancy analysis and variance decomposition analysis showed that the independent effects of stand structure explained the most changes in plant diversity. Herbaceous coverage， shrub density， tree height and soil bulk density were most closely related to plant diversity changes. Adjusting stand structure would be a simple and reliable way to improve plant diversity， and the above results provided data support for stand management in Daxing’anling Mts.

To complement and improve the community composition and structural characteristics of the summit mossy dwarf forests in Southwest China， based on the community survey data of the 1 hm² forest dynamic plot（FDP）， the Center for Tropic Forest Sciences（CTFS） standard was used to investigate all woody trees with DBH ≥ 1 cm in the plot. Then， ten standard plots（a total of 0.6 hm²， 20 m×30 m each） were selected from the 1 hm² FDP， and all vascular plants within the 0.6 hm² plot were investigated and counted by plant community inventory. The species composition and community structure were analyzed by the aspects of species richness and quantitative characters， and the diameter class structure of the dominant tree species. The main results were as follows： （1）there were 3 614 woody individuals from 42 species， 32 genera， 20 families， with DBH≥1 cm within the 1 hm² FDP； in the 0.6 hm² plot， there were 103 species of vascular plants in 42 families， 67 genera and 1 536 individuals of 24 woody species with height≥3 m； （2）Rhododendron sinofalconeri was， absolutely dominant in the community， with important values 3-4 times higher than those of the secondary dominant species； （3）The age structure of the whole community showed a “L” shape； however， Rhododendron sinofalconeri was dominant in adult individuals， being different from other dominant species； （4）The community was composed of tree， shrub and herb layers as well as epiphytes and parasitic plants， and named as Rhododendron sinofalconeri， Clethra delavayi var. yuiana， Illicium tsaii summit mossy dwarf forests. In the Bozhu Mountain， Wenshan county， Yunnan， China， the mossy dwarf forest community was rich in species， stable in composition， prominent in dominant species and good in their regeneration. The canopy appearance of the community was flat， and the community succession was in a mature forest state.

The fixed monitoring plot was conducted in the Xilinhe National Nature Reserve to analyze tree species diversity， dominant species niche， interspecific associations and community stability in the Piceakoraiensis-Abies nephrolepis-Pinus koraiensis forest community by using a series of analysis methods including the α diversity index， the niche determination， the variance ratio（V_R）， the Chi-square test（χ² test）， the Spearman’s rank correlation coefficient test and the M. Godron stability. The results showed that： （1）the plot encompassed 20 tree species， 14 families and 14 genera， with a balanced distribution of trees， and the α diversity index was high； （2）the community niche overlap index was relatively high， but the cases with large （>0.7） or small（<0.4） niche overlap index were rare with a moderate degree of niche differentiation； （3）the overall correlation of the community was nonsignificant positive， and the interspecific correlations among the main tree species were mainly positive and nonsignificant correlation with strong interspecific independence； （4）the stability of M. Godron analysis fell to the point（32.79， 67.21） and was far from the stable point （20， 80）， indicating poor community stability； （5）P. koraiensis had the highest importance value and niche width in the sample plot， the average niche overlap index with other tree species was higher than the average value of the sample plot； the species was dominated by large-diameter individuals， and the relative frequency among tree species was low. Therefore， during the restoration process of Piceakoraiensis-Abies nephrolepis-Pinus koraiensis forest， the appropriate artificial intervention should be carried out to promote the recovery of Pinus koraiensis population， to regulate interspecies relationships， to enhance interspecies association strength， and to strengthen monitoring and protection of rare plant populations when community stability declined.

Betula costata is a valuable timber and ornamental tree species in northeast China. The seed vigor and growth traits of different half-sib families were systematically compared， and a reference for selecting Betula costata superior family would be provided. Variance analysis and correlation analysis on thousand seed weight， germination rate， germination energy， germination index， sapling height， and base diameter were conducted by using 30 Betula costata half-sib families as materials， and principal component analysis was used to evaluate comprehensively the tested families. The results showed that there was an extremely significant difference in thousand seed weight， germination rate， germination energy， germination index， height， and base diameter among families， respectively. The family heritability of each trait was higher than 0.88. There was an extremely significant positive correlation between different traits. Based on the result of principal component analysis， JL6， JL18， JL22， JL7， JL25， and JL4 were selected as the superior families. The average of the thousand seed weight， germination rate， germination energy， germination index， sapling height， and base diameter of superior families were 19.62%， 15.97%， 15.31%， 26.81%， 32.15%， and 14.49% higher than the total average， respectively. The genetic gains of thousand seed weight， germination rate， germination energy， germination index， sapling height， and base diameter of superior families were 19.46%， 22.67%， 22.79%， 24.07%， 32.07%， and 14.44%， respectively. The mother tree of the above superior families could be preliminarily determined as the preferred mother tree for Betula costata seed collection.

Isopentenyl pyrophosphate isomerase（IPP） is responsible for the reversible isomerization of isopentenyl pyrophosphate and dimethylallylpyrophosphate（DMAPP）， playing an important role in the biosynthesis of downstream terpenoid products. In this paper， 31 IPP genes were identified from genomes of various mono- and dicotyledonous plants such as Oryza sativa and Arabidopsis thaliana by bioinformatics method. Phylogenetic analysis indicated that these IPPs were divided into three clades， in which those from monocotyledon plants formed a monophyletic clade. IPPs within the same clade shared similar domains and might have similar biological functions. The analysis on cis-regulatory elements of O. sativa and A. thaliana IPP genes exhibited multiple response elements such as drought response elements. Finally， quantitative PCR results showed that the expression patterns of IPP transcription levels in O. sativa and A. thaliana were diversified. These above results provided theoretical basis for systematic understanding and further application of IPPs.

In order to explore the genetic background of tulip germplasm resources， accurately evaluate and screen excellent germplasm for genetic improvement of tulips， the genetic background of 40 tulip varieties was analyzed by SRAP molecular markers， and their genetic diversity and relationships were clarified， respectively. The results showed that out of 43 pairs of SRAP primers， 21 pairs of polymorphic primers were available for genetic diversity analysis of tulips， and 249 clear and stable bands were amplified in the 40 tulip varieties， of which 245 were polymorphic bands with a polymorphism rate of 98.39%. The genetic similarity index of the 40 tested varieties ranged from 0.502 0 to 0.867 5， and the genetic diversity parameters including the number of alleles（N_{\mathrm{a}}^{\mathrm{*}}）， number of effective alleles（N_{\mathrm{e}}^{\mathrm{*}}）， Nei’s gene diversity index（H^*）， Shannon’s information index（I^*）， and polymorphic information content were 1.981 0， 1.514 9， 0.304 2， 0.460 3， and 0.321 2， resp-ectively， indicating rich genetic diversity in the tested materials. Cluster analysis and principal coordinate analysis showed that the 40 tulip varieties were classified into two major groups， among which ‘Christmas Magical’， ‘Banja Luka’， and ‘Madame Lefeber’ were relatively distant genetic relationships from other varieties and had certain differences in their genetic backgrounds.