Reviewed the classification progress of vegetation in the world and in China， a new classification system and nomenclature of Chinese vegetation was presented based on appearance， structure， dynamics， species composition， formation causes and habitat of the community. The principal hierarchy of classification ranks including Vegetation type， Alliance and Associaton were steady， but the word “Alliance” was suggested to replace the word "Formation". Classes of vegetation types， Subclasses of vegetation types， and Group of vegetation types were introduced as supplementary ranks above the vegetation type. It was not recommended to set too many auxiliary ranks below the vegetation type. The high classification units of the natural vegetation classification system were concluded into 3 vegetation classes， 7 vegetation subclasses， 12 vegetation type groups， and 76 vegetation types respectively. The vegetation types were assigned classification codes. The main differences between the new classification system and the Chinese vegetation classification system in 1980 was that the tundra， desert， and swamp were considered as a vegetation habitat instead of being described as a type of vegetation respectively. In order to distinguish between the same concepts in Geomorphology and Physical geography， vegetation subclasses and vegetation types of Fasciculate-leaved forest were added to the new system， and bamboos were individually classified into forest vegetation and shrub vegetation. The herbaceous vegetation was divided into steppe， meadow and grassland respectively， according to the ecological type of the herbs， formation causes of vegetation and community dynamics. As one of the important works of vegetation classification， the methods of vegetation nomenclature were also provided.
We found specimens of Scariola orientalis（Asteraceae） in Tibet. Finally， we determined that its current domestic distribution is in Tibet.
According to the system published by Sima & Lu in 2012， four new combinations of the genus Dugandiodendron Lozano-Contreras in Magnoliaceae were reported， including Dugandiodendron bankardiorum （M.O.Dillon & Sánchez-Vega） Sima & Hong Yu， Dugandiodendron coronatum（M.Serna， C. Velásquez & Cogollo） Sima & Hong Yu， Dugandiodendron jaenense（Marcelo-Pe?a） Sima & Hong Yu and Dugandiodendron roraimae（Steyermark） Sima & Hong Yu.
In order to explore the planting of Fritillaria unibracteata at different altitudes， to expand its industrial development space and slow down the contradiction between its output and market demand， and pot experiments were carried out at 5 altitudes（i.e.， 1174m， 1784 m， 2371 m， 3076 m， and 3413 m above the sea level respectively）. The results indicated that both germination and leaf spreading stages of F. unibracteata significantly advanced with the decreased altitude（P<0.05）. The withering stages significantly advanced with the decreased altitude（P<0.05）， but they were not significantly different（P>0.05） between high altitudes （i.e.， 3 076 and 3 413 m）. The length of growing season increased first and then decreased with the decreased altitude， and the longest growing season was（114.83±3.59） days at 3 076 m. Both the plant height and single leaf area increased first and then decreased with the decreased altitude， and the maximum values were（11.00±0.70） cm and （7.71±0.87） cm2 at 2371 m. The lengths of bulb transverse axis and longitudinal axis increased first and then decreased with the decreased altitude， and the maximum values were（10.63±0.87） mm and （12.11±0.72） mmat 3 076 m. The results showed that， considering the length of growing season and bulb size of F. unibracteata， low altitude cultivation could be carried out in the range of 2 371-3 076 m.
To further understand the morphological and structural diversity in early ontogeny of angiosperms， the developmental process and characteristics from zygote to seedling stage were studied. The results showed that the embryo development of G. scabra belonged to Solanad type， endosperm development was nuclear type， the differentiation of seed embryo was incomplete when seeds scattered from the capsule， and most seeds developed to the stage of heart-shaped embryos or torpedo embryos. When the seed germinated， the radicle relied on the elongation of the hypocotyl cells to break through the seed coat， forming a root ring at the junction of the hypocotyl and the radicle， and then the root ring hair developed on the root ring. The hair extension grew faster than the radicle at the initial stage. In the development of the radicle， normal root hairs gradually appeared at the tip. The seedlings in the cotyledon state were stagnated for at least 10 days before true leaf development was seen， but while the growth was stagnant on the ground， the underground radicle continued to grow. The characteristics of these organ development sequences reflected the original aquatic relict of the ancestors， and adapted to more arid habitats， which was the further evolution of the secondary terrestrial species.
In order to understand the genetic background of Cordia subcordata， we used the root tips as materials to investigate optimal sampling and pretreatment conditions， and the cells with better chromosome dispersion were selected for karyotype analysis. The results showed that：（1）The best sampling time of C. subcordata was from 9：30-10：00 am and from 14：00-14：30 pm and the optimal pretreatment was immersing the root tips in saturated p-dichlorobenzene for 2 hours； （2）C. subcordata was diploid， with 32 chromosomes， totally 16 pairs. The karyotype formula was 2n=2X=32=32m， and the karyotype was “1A”. The absolute length variation range of chromosome was 0.38-0.69 μm， and the relative length（%） varied from 4.48-8.24. The relative length composition was 2n=2L+14M1+14M2+2S. The karyotype asymmetry coefficient（As.K%） was 58.40%. These results would provide references for chromosome preparation and karyotype analysis， and laid a foundation for cytogenetic and epigenetic studies on C. subcordata.
To explore the effects of different nutrient additions on the growth and nutrient content of Populus euramericana “N3016” × P. ussuriensis， Populus simonii × Populus nigra and Populus ussuriensis， and to reveal the nutrient demand and utilization rules of poplar， and to provide a reference for nursery cultivation of poplar seedlings， P. euramericana “N3016” × P. ussuriensis， Populus simonii × Populus nigra and Populus ussuriensis were used as materials， 3 factors（N： nitrogen， P： phosphorus， K： potassium） and 3 levels（N： 1.5， 3， 6g； P： 0.75， 1.5， 3g； K： 0.5， 1， 2g， for per plant respectively.） L9（34） orthogonal experimental design were uesd， plants with no fertilization as control， and the effects of different nutrient supply levels on the growth dynamics and nutrient distribution of different poplars were studied respectively. The results showed that：①Different nutrient supply had significant effects on the growth of seedling height and ground diameter of P. euramericana “N3016” × P. ussuriensis， Populus simonii × Populus nigra and Populus ussuriensis from the middle of July. The height and base diameter growth index of three tree species was the highest at NPK 1 level respectively. The biomass of P. euramericana “N3016” × P. ussuriensis was the highest when N， P and K was selected at 3， 1 and 2 level respectively. The biomass of Populus simonii × Populus nigra was the highest when N， P and K level was 2， 1， 1， respectively. The biomass of Populus ussuriensis was the highest when N， P and K level was 1， respectively. The effects of N， P and K on the growth indexes of P. euramericana “N3016” × P. ussuriensis and Populus simonii × Populus nigra was N>P and K， while the effects of N， P and K on the growth indexes of Populus ussuriensis was K>N and P. ②The accumulation of nitrogen， phosphorus and potassium in roots， stems and leaves of P. euramericana “N3016” × P. ussuriensis， Populus simonii × Populus nigra and Populus ussuriensis was N>P， K. The accumulation of nitrogen in each organ of the 3 varieties was greater than that of phosphorus and potassium. Among the 3 poplar varieties， the accumulation of 3 kinds of nutrients in each organ was significantly different. The distribution ratio of total nitrogen accumulation in 3 varieties was stem>leaf>root. The distribution ratio of phosphorus accumulation of P. euramericana “N3016” × P. ussuriensis and Populus simonii × Populus nigra was stem>leaf>root. The order of Populus ussuriensis was leaf>stem>root. The distribution of potassium accumulation of P. euramericana “N3016” × P. ussuriensis and Populus ussuriensis was leaf>stem>root. The distribution of potassium accumulation of Populus simonii × Populus nigra was higher than that of stem>leaf>root. ③Through the comprehensive analysis of each index， it was concluded that the optimal fertilization scheme of Populus ussuriensis， P. euramericana “N3016” × P. ussuriensis and Populus simonii × Populus nigra was N1P1K1， that was， N 1.5 g， P 0.75 g， K 0.5 g， for per plant respectively.
In order to select plant for vegetation restoration and landscape reconstruction on the side slope of the dump in Heilongjiang Duobaoshan Copper Mine， the investigation of background plants in the mining area and the investigation of cultivated plants in Heilongjiang Province was based on， and the analytic hierarchy process（AHP） was used. The results showed that a screening evaluation system was constructed including 10 specific indicators in 4 aspects of ecological adaptability， ecological protection， greening effect， and economic efficiency， and 74 plants were sorted by weight， and finally the dumping ground suitable for Duobaoshan Copper Mine were screened out totally of 20 species of trees， shrubs， and herbs for vegetation restoration， which would provide plant for the improving the ecological environment of mine dumps and landscape reconstruction， and for practical reference for the selection of ecological restoration for other mine dumps in cold regions of China.
Polyaspartic acid（PASP） is an environment-friendly polymeric substance that has been frequently used as fertilizer synergist and sustained release agent in agriculture. In order to investigate the effects of PASP on nitrogen uptake and utilization in poplar seedlings， 12 gradient treatments of different concentrations of nitrogen and PASP were set in the hydroponic-grown poplar hybrid ‘Nanlin 895’ seedlings. The results showed that the addition of PASP in nutrient solution had an obvious promoting effect on poplar growth and development when nitrogen supply was inadequate， and it improved the plant height， number of leaves and shoot biomass and the utilization efficiency of nitrogen， whereas the root to shoot ratio and nitrate concentration in seedlings was decreased. However， the exogenous supplement of PASP aggravated the stress of high nitrogen under the condition of high nitrogen. The results demonstrated that PASP could be used as fertilizer synergist for poplar， and the appropriate addition of PASP under insufficient nitrogen conditions would promote growth performance of poplar seedlings.
Taxus species are imminent extinction due to objective factors such as slow growth speed， decreased breeding ability， and weak competition， as well as subjective factors including overexploitation and habitat destruction. Therefore， the protection of Taxu resources via breeding methods has become the focus of research. In this study， three Taxus species in China（Taxus cuspidata， T. mairei， and T. media） were selected as materials， and the stem tissues with axillary buds were selected as explants， and the different phytohormone combinations on the initiation， proliferation and rooting of axillary buds were systematically investigated. MS+1.0 mg·L-1 6-BA+0.2 mg·L-1 NAA was finally determined as the optimal medium for axillary bud initiation， and MS+0.4 mg·L-1 6-BA+1.0 mg·L-1 NAA was the suitable medium for adventitious bud proliferation. It was found that all three Taxus species could effectively initiated and proliferate in the above-mentioned medium. Moreover， WPM+0.8 mg·L-1 NAA+0.2 mg·L-1 IBA medium was found to promote the rooting of adventitious buds of T. cuspidata， and the WPM medium without adding any plant hormones was beneficial for the subsequent growth of rooted seedlings. Overall， this study established a simple and effective method for in vitro propagation of Taxus species， which would provide the technical support for the protection and sustainable utilization of Taxus resources in China.
Based on the transcriptome database of Dendrocalamus farinosus， a MYB transcription factor named DfMYB3 was cloned from the leave of D. farinosus. Its open reading frame length was 1 287 bp， encoding 428 amino acids， and GenBank accession Number was KY963358. The conserved domain analysis showed that DfMYB3 had the typical SANT domains and DNA-Binding domains. Phylogenetic tree analysis showed that DfMYB3 clustered with R2R3-MYB transcription factors in Saccharum， Arabidopsis and Populus. Subcellular localization showed that DfMYB3 protein was expressed in both the nucleus and cell membrane，and was more significant in the nucleus. The sequence of 5′ flanking of DfMYB3 gene about 2 000 bp was cloned by chromosome walking method. Analysis of PlantCARE online software showed that the sequence had typical promoter characteristics， and contained hormones responsive elements such as GA， ABA， MeJA as well as stress responsive elements such as drought. The expression level of DfMYB3 gene was significantly up-regulated after 100 μmol·L-1 GA and 100 μmol·L-1 ABA treatment， indicating that DfMYB3 gene was involved in response to GA and ABA treatments. In order to explore the function of DfMYB3 promoter， the expression vector of GUS gene fused with DfMYB3 promoter was constructed and genetically transformed into tobacco. The results showed that GUS signal was detected in both leaf and stem of transgenic tobacco， especially in the veins.
Using SNP loci to estimate the genetic distance between the parents of Pinus elliottii × P. caribaea， and effectively predicting the heterosis of tree height， diameter at breast height（DBH） and timber volume in their hybrids， which provides a reference for molecular marker-assisted mating design and breeding. Using SLAF-seq technology to sequence and analyze the DNAs of 131 germplasm resources from the parents of P. elliottii × P. caribaea， and valid SNP markers were obtained. Based on these SNP loci， the genetic distances between 13 parents of P. elliottii × P. caribaea were estimated by using MEGA 5.0 software， and cluster analysis were performed. The heterosis of the growth traits and the correlation between heterosis and SNP genetic distance of the 13 cross combinations were analyzed and calculated by using SPSS software. A total of 53 952 polymorphic SLAF tags and 96 736 valid SNP markers were obtained by SLAP-seq. The genetic distance between the parents of P. elliottii × P. caribaea was arranged from 0.425 1 - 0.490 6， and the correlation coefficients between SNP genetic distance of the parents and heterosis of their hybrids in tree height， DBH and timber volume were 0.680， 0.648 and 0.624， respectively. All three correlation coefficients reached a significantly positive correlation level. Utilizing SLAF-seq technology can obtain massive SNP loci. Based on these SNPs， the genetic distance between parents of P. elliottii × P. caribaea can be estimated， and the heterosis of tree height， DBH and timber volume in the hybrids can be effectively predicted.
To explore the expression characteristics of BZR1 gene under abiotic stress and hormone induction of brassinosteroid（BR） signaling on the growth and development of Fraxinus mandshurica and response to environmental stress，the target gene was cloned from F. mandshurica by PCR and its molecular structures were analyzed by bioinformatics. The expression patterns of FmBZR1 under low temperature， salt stress and ABA， IAA and GA3 hormones were investigated by real-time fluorescence quantitative PCR. Bioinformatics analysis showed that the FmBZR1 gene was 984bp， encoding 327 amino acids. FmBZR1 was a hydrophilic protein， and had high homology with BZR1 protein of Olea europaea var. sylvestris. The results of abiotic stress and hormone induction showed that the expression of FmBZR1 gene was significantly different from that of control group. The highest expression level of FmBZR1 gene was at 6 h after low temperature treatment and 24 h after salt treatment， which were 1.98 times and 10.13 times higher than that of the control group. After stress with ABA， IAA and GA3 for 3 h， the expression of FmBZR1 gene was the lowest， which was 0.52 times， 0.41 times and 0.50 times of the control group； after treatment GA3 for 24 h， the expression level of FmBZR1 gene was the highest， which was 6.23 times of the control group. FmBZR1 gene played a key role in the development and stress process of F. mandshurica.
To establish the tissue culture system of Gentiana rhodantha， the proper explant， disinfecting methods， the best medium for seedling proliferation， for rooting and methods for transplanting were studied respectively. The results showed that the stems with node were the best explants， and the survival rate reached 80% with no contamination by disinfecting with 5% sodium hypochlorite for 10 min； the best medium for bud proliferation was： MS+0.1 mg·L-1 IBA+2.5 mg·L-1 ZT with a proliferation coefficient of 8.94， and the best rooting medium was： 1/2MS+0.3 mg·L-1 IBA with a rooting rate of 100%； the best transplant medium was perlite∶turf=1∶1 with a survival rate up to 100%. This study established a rapid propagation system， provided the technical support for the factory seedling and large-scale cultivation of G. rhodantha.
The experiment was conducted to study the leaf C， N， P stoichiometric characteristics of Cupressus funebris plantations in Sichuan Province and their responses to site change and age group for understanding the leaf nutrient distribution patterns of C. funebris in different age groups and site types. In order to determine the effects of site and age group on the leaf stoichiometric characteristics of C. funebris plantations， 70 standard plots were selected for the site classification in the main distribution areas of C. funebris plantations. Leaves from different age groups（young stand， half-mature stand， and near mature stand） of C. funebris werecollected， and the C， N， P contents of leaf were measured respectively. The plots were classified into 2 site type districts， 4 site type groups， 8 site type subgroups and 17 site types. The average leaf C， N， P contents of C. funebris in Sichuan were（550.55 ± 18.08） g·kg-1， （9.39 ± 0.20） g·kg-1， （0.95 ± 0.12） g·kg-1， and the C∶N ratio， C∶P ratio， N∶P ratio of which were 58.70 ± 3.04， 583.68 ± 44.59， 9.93 ± 0.37， respectively. Leaf C， N， P contents and C∶N， C∶P， N∶P ratios were all affected by site type and age group significantly（P<0.05）. Within the same age group， the leaf C content， C∶N ratio and C∶P ratio of C. funebris in the mountainous site type district were significantly higher than those in the hill site type district； in the acid purple soil site type group were significantly higher than those in the calcareous purple soil site type group in each district； in the lower slope site type subgroup were significantly higher than those in the middle and upper slope site type subgroup and the top slope site type subgroup in each group of hill site type district； in the thin soil site type of hill site type district were significantly higher than those in the medium soil site type； in the sunny slope site type subgroup were significantly higher than those in the shady slope site type subgroup in each group of mountainous site type district； and in the groove site type of mountainous site type district were significantly higher than those in the slope and ridge site type， however， the leaf N and P contents of C. funebris showed the opposite trends. Within the same site type， the leaf C content， C∶N ratio and C∶P ratio increased continuously， and the N and P contents decreased continuously from the young stand to the near mature stand. The growth of C. funebris plantations may be restricted by N and more obvious in the early growth stage. In summary， we suggested to cultivate the C. funebris plantations in the site conditions such as the combination of “acid purple soil in groove on sunny slope of mountain” or “thin acid purple soil on lower slope of hill”， and apply N fertilizer in early growth stage to alleviate the possible nutritional restrictions.
“Flora Reipublicae Popularis Sinicae ”and “Flora of China” had different opinions on the subspecies treatment of Begonia grandis Dryander， which could not be applied in practice according to their classification criteria， and the issues still remain unsolved in the subspecies classification of this species. In order to understand intraspecific diversity of B.grandis， a numerical classification study was conducted with 33 phenotypic traits from 39 wild B.grandis populations. By quantity characters variation analysis， quality traits genetic diversity analysis， principal component analysis and R-type cluster analysis， the main traits were screened out from 33 traits for Q-type cluster analysis. The phenotypic diversity of B.grandis was rich， the variation coefficient of quantity traits was 0.077-0.441， and the Shannon-Wiener diversity index of quality characters was 0.287-1.483. Principal component analysis showed that 33 traits could be integrated into 6 principal components， and the cumulative contribution rate was 72.28%. R-type cluster analysis showed that the characters were relatively independent except for the correlation between leaf size and male flower size. Q-type cluster analysis classified 39 B.grandis populations into four groups with male flower size， leaf size， plant size， leaf color， which was inconsistent with three subspecies classified by Flora of China. Therefore， it was necessary to combine the molecular evidence to discuss the rational intraspecific classification of B.grandis in the future. It was interesting that Japanese naturalized populations of B.grandis very possibly originated from Tianmu Mountain population in Zhejiang Province.
Vegetation distribution and biodiversity maintain in riparian zone have been a hot topic recently， however， few studies have been conducted on the ecological adaptation of the endangered riparian dioecious trees. We explored the sex-related difference of Cercidiphyllum japonicum adults in number， morphology， leaf nitrogen（NRE）-and phosphorus-（PRE） resorption efficiencies， soil contents of water， nitrogen and phosphorus and the relationships of NRE or PRE with leaf N and P， soil contents of water， N and P or plant morphology. The number of females significantly decreased rather than males with increasing distance to riverside， resulting in a decrease in the sex ratio（females/males）. In long distance， the sex ratio was significantly male-biased（female/male=0.289； χ2=4.57， P<0.05）， N content of green leaves and PRE of males were higher than that of males， while these traits were similar both sexes near riverside. In addition， male NRE or female PRE was related to green leaf， soil water and nutrient， and height of C.japonicum（especially for males） were positive with NRE and PRE. Our results showed that there were sex-specific adaptive responses to river distance in C.japonicum， and female and male leaf NRE and PRE differently respond to leaf nutrient or soil factors. The requirement of near riparian habitat for females might limit its population distribution.
In order to explore the differences of metabolites between wild and cultivated Taxus cuspidata， nontargeted metabolomics was analyzed. Using GC-MS and multivariate statistical analysis to compare the bark of wild species and cultivated species， the differences in their metabolites were found. A total of 45 significant metabolites were detected， including 4 amino acids， 10 organic acids and some sugar alcohols. Among them， 22 metabolites were up-regulated and the 23 metabolites were down-regulated. KEGG pathway analysis showed that seven pathways had significant effects， including sulfur metabolism， arginine and proline metabolism， pentose phosphate pathway， unsaturated fatty acid biosynthesis， galactose metabolism， alanine， aspartate and glutamic acid metabolism， phenylpropanoid biosynthesis. The metabolites such as amino acids and organic acids were highly expressed in cultivated T. cuspidata. The stress resistance of wild T. cuspidata was weaker than that of cultivated T. cuspidata. However， the expression of carbohydrate was higher in wild species. T. cuspidata wild species had better glucose metabolism ability to resist low temperature stress. The results provided a theoretical basis for the protection of T. cuspidata wild species and stress resistance mechanism of T. cuspidata.
The afforestation of Pinus koraiensis under canopy is an important management method to promote the transformation of natural secondary forest to broad-leaved Korean pine forest. For different tree species and composition ratio， the forest afforestation environment is very different in the diverse types of natural secondary forest. However， there was no research on the improvement of P. koraiensis varieties in Korean pine afforestation under canopy of natural secondary forest. In view of problems above， the provenance test of Korean pine was performed in different types of natural secondary forests， such as mixed forests， Poplar-brich forests， and hardwood forests， in Lilin experimental forest station of Xiaoxing’an mountains. The results showed that there were significant or extremely significant differences in diameter above ground， height， 7-year high growth， one-year high growth， and conservation rate of Korean pine provenances among different types of natural secondary forests； the Poplar-brich forests exhibited the best performances of Korean pine afforestation under canopy， followed by hard broad forest hardwood forests by turn； the Tieli was the superior provenance for afforestation in Poplar-brich forests and mixed forests， while the Wangqing provenance showed the best performance in the excellent provenance in hardwood forests.
As one of the three fast-growing tree species in the world， Eucalyptus has high value in economic， ecological， medicinal and other aspects. Due to the high genetic heterozygosity of Eucalyptus， many major economic traits might be jointly regulated by multiple genes， and conventional gene editing methods could not meet the requirements for efficient screening of Eucalyptus target gene editing and transformation. Using mCherry fluorescent protein as a selection marker might reduce the identification workload after transformation. In this study， a CRISPR/Cas9 vector containing the 35S promoter to promote the mCherry marker gene was constructed using Eucalyptus urophylla as the material to perform efficient visual editing of the Eucalyptus gene. The mCherry fluorescent protein was used as the selection marker to screen positively transformed progenies， and the adventitious bud genome containing fluorescent markers were extracted for PCR identification and analysis. The results showed that the editing vector PHEE401-35S-mCherry was successfully constructed. After the callus of Eucalyptus urophylla transformed， there was obvious red fluorescence under the light of 580 nm， and the target fragment with the same size as 35S-mCherry band was amplified by PCR identification. The study provided a visual screening method for the Eucalyptus gene editing.
To extract the main components from Carthamus tinctorius L.， the Box-Behnken design method and response surface methodology were used to optimize the extraction process of C. tinctorius L.； Hydroxy-safflower yellow A and kaempferol-3-O-rutinoside were the main flavonoids in C. tinctorius L. petals . The results showed that Ultrasonic extraction method were the optimal extraction technology： using 57% methanol as solvent， liquid-material ratio was 0.1∶25 g·mL-1， ultrasonic temperature was 70℃， extraction time was 45 min， ultrasound power was 177 W， Under these conditions， hydroxy-safflower yellow A extraction yield was 1.74%， kaempferol-3-O-rutinoside extraction yield was 1.53%. The safflower main ingredient extraction was recommended to use ultrasonic extraction.
Scanning electron microscopy（SEM） had been widely used in the study of palynomorphology. However， it was difficult to directly observe the morphology of pollen grains in Pollinium. In this paper， we studied the sample preparation method for obvervation pollen grains in pollinium. The pollinium of Dendrobium cariniferum Rchb. f. was used as the material， based the conventional SEM sample preparation， the pollen grains inside the pollinium were exposed by the conductive double-sided tape breaking method and then observed by SEM. The stereoscopic shape， size and surface texture of pollen grains were observed clearly under the SEM. This method was simple， easy to operate and can be used as a general method to observe the morphology of pollen grains in pollinia by SEM after further optimization.
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