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.
In order to better understand the intraspecific diversity of Saxifraga stolonifera and to explore the possibility of its classification， and to provide reference for the resource protection and innovative utilization of S. stolonifera germplasms， 33 traits from 43 populations of S. stolonifera in China were investigated， and the diversity of phenotypic traits was analyzed by numerical trait variation analysis， qualitative trait genetic diversity analysis， correlation analysis， principal component analysis and cluster analysis. The results showed that： （1）The coefficient of variation of numerical traits was 0.05-0.67， and the diversity index of qualitative traits was 0.19-1.39， and the distribution pattern of maculation and leaf color diversity were high among populations， and the branch number and the ratio of leaf length to width of stolon were the most unstable and the most stable traits， respectively. （2）The coefficient of variation of numerical and derived traits， and the diversity index of quality traits were generally high， and the contribution rates of each principal component were relatively scattered， so it was unsuitable to classify the species into different taxa only by morphological traits. （3）There were differences in the correlation of different personality traits among populations of S. stolonifera， and significant correlations included leaf length and width， length of long lower petal and length of short lower petal， width of long lower petal and width of short lower petal， respectively. （4）Based on the results of morphological clustering， S. stolonifera in China could be divided into three branches， which exhibited certain regional character. ClusterⅠ was composed of eight Southwest populations， two East China populations， and three Northwest populations； ClusterⅡ consisted of four populations from East China， four populations from Central China， four populations from Southwest China， and one population from Northwest China， so Cluster Ⅱ was widely distributed； Cluster Ⅲ consisted of ten Central China populations， six Southwest populations， and one East China population.
Pinus koraiensis is an important tree species used as fruit in northeast China， but due to its long growth cycle， its genetic improvement progress is slow. In order to evaluate and screen the elite P. koraiensis germplasm resources， 36 half-sib families of 20-year-old P. koraiensis from Xiyang forest seed orchard in Jilin Province were used as materials， and the growth traits and wood properties of different families were investigated. The results of variance analysis showed that the differences of each trait among families reached extremely significant level（P<0.01）， and the phenotypic variation coefficients of different investigated traits was 5.89%~45.21%. Except trait straightness（0.46）， the family heritabilities of other traits exceeded 0.5， which all belonged to high heritability. Correlation analysis results showed that the growth traits such as tree height and diameter at breast height had significantly positive correlations（r>0.663）. The contents of hemicellulose， cellulose and holocellulose were significantly correlated with each other among wood traits， while only cellulose and holocellulose were negatively correlated with some growth traits among growth traits and wood properties. The results of principal component analysis showed that 14 traits constituted five principal components， and the cumulative contribution rate was 79.24%. The comprehensive evaluation method was used to evaluate 36 half-sib families， with an admission rate of 10%， three elite families（PK61， PK29 and PK22） were selected according to their growth traits， and the genetic gain of each growth trait ranged from 6.41%- 33.91%. According to wood properties， three elite families（PK16， PK78 and PK10） were preliminarily screened， and the genetic gain of each wood trait ranged from 1.08%-6.72%. Combined with growth and wood properties， three excellent families（PK61， PK29 and PK44） were selected， and the genetic gain of each index ranged from 0.27%-37.28%. The elite families selected in this study can provide the basis for the selection of improved varieties of P. koraiensis.
To protect germplasm resources and provide technical support for native garden species， the breeding system and hybrid affinity of wild Rhododendron irroratum were studied. The experiments included flowering biological characteristics， the characteristics of breeding system and the cross pollination with fine horticultural varieties of Rhododendron. The process of pollen germination and pollen tube growth were observed by fluorescence microscope， and the fruiting and seed setting were calculated. The results showed that （1） the flowering time of R. irroratum dewdrop was from late April to late May， and pollen viability and stigma receptivity decreased gradually with the extension of flowering time. （2）Hybridization index（OCI） was 3， P/O value was 343.47. （3）The main pollinator was Apis cerana. The breeding system was facultative outbred， self-compatible， requiring pollinators. （4）No apomixis was found in artificial pollination， which could automatically self-pollinate. The fruit setting rates of different strains cross-pollination， strains cross-pollination and self-pollination were 46.96%， 45.03% and 37.16% respectively. The average fruit setting rate of artificial pollination was basically consistent with that of natural pollination. （5）The hybrid incompatibility was observed in the parent for artificial cross pollination. Fluorescence microscopy revealed callose embolism in the pollen tube of the mother， which prevented the tube from extending to the ovary. Through observation， it is found that the difficulty of cross compatibility lies in pollen tube growth process.
‘Populus leucopyramidalis 1’ is an excellent poplar clone with narrow crown and saline-alkali tolerance. Due to the lack of its genetic transformation system， genetic improvement could not be achieved through genetic engineering methods. In this study， an Agrobacterium mediated genetic transformation system of ‘P. leucopyramidalis 1’ was established and the high genetic transformation efficiency was achieved. Firstly， the tissue culture seedlings were subcultured at different time periods（35， 45， 55， 65 d）， and three types of tissues（leaves， petioles， and stem segments） were taken to compare the differentiation ability， and it was determined that the leaves sub-cultured after 45 d had the strongest differentiation ability， with a proliferation ratio of 8.77. Then， leaves sub-cultured after 45 d were used for genetic transformation， and the effects of different infection conditions on the transformation rate were examined. Orthogonal experiments were established with three gradients of bacterial concentration， infection time， and co-culture time to screen the best levels of these three factors， and the transgenic strains were identified through PCR detection and GUS staining. The results showed that the optimal combination for the genetic transformation system of ‘P. leucopyramidalis 1’ was bacterial concentration OD600=0.4， infection-time 15 min， and co-cultivation time 2 d could reach the highest transformation rate 54.23%. Finally， the ‘P. leucopyramidalis 1’ transgenic strain of BtCry3Aa insect resistant gene using this genetic transformation system was obtained， and the results proved that this system could be an effective method for genetic improvement of ‘P. leucopyramidalis 1’.
Populus simonii×P. nigra is a fast-growing and cold-tolerant tree species with elite wood properties in northeast China. In order to produce a new forest germplasm with more widely planting and improved drought tolerance， this study successfully generated transgenic P. simonii×P. nigra using PsnNAC007， a key drought response transcription factor gene. Growth characteristics， drought tolerant ability， net photosynthetic rate（Pn）， transpiration rate（Tr）， stomatal conductance（Gs）， water conductance， cell morphology and wood components of overexpressed PsnNAC007 transgenic plants were analyzed respectively. The results showed that there was no significant difference in growth between transgenic and wild-type plants， but drought survival rate was increased by 26.15%. Under drought condition， transgenic plants exhibited reduced Cleaf and Tr， improved water use efficiency， and lower water conductance loss. Anatomical analysis showed that the overexpression of PsnNAC007 led to more and smaller stem xylem vessels， which were conducive to the continuous and efficient water transport in plants under drought conditions. Based on wood components analysis， lignin deposition in stems of transgenic plants was increased significantly， and monosaccharides that constituted cellulose and hemicellulose showed no significant change.
In order to clarify the phenotypic variation degree and regularity of flower organ traits in distant hybrids of Catalpa bungei， 12 distant hybrid species of C. bungei were used as materials， statistical analysis methods such as variance analysis， correlation analysis， and cluster analysis were used to study their phenological characteristics， inflorescence traits， flower traits， and color traits during flowering. The results showed that there were significant differences in phenological characteristics during the flowering period of the distant hybrid species of C. bungei. The hybrid of C. bungei and C. ovata was pseudo three-branch， with strong differentiation ability of flower buds， and multiple rounds of flowering in the year of grafting， and the flowering period of over 100 days， exhibited maternal traits. The floral organ characteristics of hybrid species of C. bungei were significantly different， with seven to nine rounds of lateral branches in the inflorescence axis， and the main axis was an infinite inflorescence， and the lateral branches were dichasium， and the transition from the bottom to the top was a cyme inflorescence， which was a transitional trait from a limited inflorescence of C. bungei to an infinite inflorescence of C. ovata. The variation ranges of total flower length， flower tube diameter， flower tube length， corolla width， peduncle length， pistil length， anther length， stamen length， and sterile stamen length were 35.42-50.36， 10.84-16.13， 16.57-24.68， 31.58-44.87， 9.07-31.99， 19.44-27.52， 4.85-5.89， 13.93-21.10， 3.66-6.79 mm， respectively. The variation coefficient ranged from 10.88%-31.02%， and the diversity index ranged from 1.36-1.93. Based on the nine traits， the 12 hybrids were clustered into three types： large flower type， medium flower type and small flower type. There were significant differences in flower color among C. bungei hybrids.The values of L*， a* and b* were used to cluster the labellum flower spots color of the 12 hybrids into three categories， namely pinkish purple， purplish red and purple.
Leaf is the main photosynthetic organ， and the leaf morphology beneficial for photosynthesis has become an important breeding target. atscamp was screened from the Arabidopsis thaliana mutant library（about 6 000 lines） with wide leaves. Tail-PCR analysis revealed a T-DNA insertion at the AT1G11180 locus， which encodes a secretory carrier membrane protein（SCAMP）. RT-PCR showed that the transcriptional expression level of the gene was basically zero. The leaf width and area of the mutant were significantly larger than those of wild type plants（P<0.01）， while the crown diameter was essentially unchanged. Additionally， chlorophyll content， chlorophyll maximium fluorescence， and photosystem II potential photochemical efficiency were all increased in the atscamp mutant（P<0.05）. Correspondingly， the mutants showed significant increases in transpiration coefficient（Tr）， net photosynthetic rate（Pn）， and leaf water use efficiency（WUE）（P<0.05）. Spatial-temporal specific expression analysis of the AT1G11180 gene revealed that the gene was highly expressed only in leaves， with low expression levels in other organs， and the gene expression gradually increased with the development and maturity of plants. The results suggested that AtSCAMP might play an important role in leaf shape development.
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.
