Study On Stem And Leaf Structure And SSR Genetic Diversity Of Cerasus

Cerasus are widely used in ecological landscapes and urban gardens,because of their high economic value,especially high ornamental value.16 kinds of Cerasus plants introduced in Hunan Forest Botanical Garden were taken as the research materials.Mature leaves and 1-year-old stems of Cerasus were used as the experimental materials,and the anatomical structure of stems and leaves of Cerasus were observed by plant microscopy.SSR molecular markers were used to study the genetic diversity of Cerasus.The research results can provide morphological and anatomical basis for the systematic taxonomic study of Cerasus.The main results go as follows:(1)Observation and analysis of the annual secondary structure is composed of pith,xylem,vascular ray,cambium,phloem,cortex,pericyte and epidermis from the inside to the outside,but structural parameters of different plants showed differences(P<0.05),among which the stem diameter,pith diameter and pith rate of Cerasus discoidea 'Hangzhouzao' were significantly less than other plants of Cerasus,and the pith diameter,pith rate and pericyte rate of Cerasus serrulata var.lannesiana 'Erect'were significantly more.The xylem rate of the Cerasus conradinae and Cerasus subhirtella were significantly more than other plants of Cerasus.The phloem rate of Cerasus discoidea,Cerasus discoidea 'Hangzhouzao' and Cerasus×yedoensis'Somei-yoshino' were significantly more.(2)Observation and analysis of stem vessel element using wood isolation method showed that there were five types of secondary wall thickening types in the vessel elements,among which the spiral vessel and reticulate vessel were the most common.There are significant differences in the inner diameter,length,tail length and density of the vessel elements(P<0.05).Most of the vessel elements were single perforated plates,while a few are multi-perforated plates and trapezoidal perforated plates.The end walls were inclined and tailed.The shape and length of the tail were different from the thick short to the slender tail and the proportion of vessel elements without tails at both ends is the smallest.(3)Observation and analysis of leaf anatomical structure using paraffin-making technology showed that the leaves were obviously differentiated into three parts:epidermis,mesophyll,and vein.The mesophyll were divided into palisade tissue and sponge tissue,and the main veins were open semi-circular structures.The leaf anatomical structure parameters were significantly different among different Cerasus(P<0.05).The upper epidermis thickness,leaf thickness,palisade tissue thickness and sponge tissue thickness of Cerasus discoidea and Cerasus discoidea'Hangzhouzao' were significantly lower than other Cerasus.The thickness of epidermis,leaf thickness and palisade tissue of Cerasus serrulata'Hanagasa' were significantly higher than those of other Cerasus.The ratio of palisade tissue thickness to sponge tissue thickness of Cerasus yunnanensis is significantly more than other Cerasus.(4)Observation and analysis of leaf epidermal micromorphology using epidermal separation method showed that the shape of the upper epidermal cells were mainly polygonal,and the anticlinal wall pattern were mainly straight.The shape of the lower epidermal cells were mainly irregular,and the anticlinal wall pattern were mainly arched.The shape of the stomata were mostly elliptical,and the type were irregular which is only distributed on the lower epidermis.There is "T" shaped thickening of the poles in Cerasus dielsiana,Cerasus campanulata,Cerasus subhirtella,Cerasus×kanzakura 'Rubescens' and Cerasus serrulata var..lannesiana'Erect'.There were significant differences in stomatal size among different species(P<0.05).The stomata length,stomata width and single stomata area of Cerasus discoidea and Cerasus discoidea 'Hangzhouzao' were significantly smaller than other samples,but the stomata density was significantly higher than other Cerasus.(5)Microsatellite SSR molecular labeling results showed that 10 pairs of SSR primers(SC7YT,SC23YT,EMPaS11A,BPPCT008,UDP98-022,CPSCT021,PTCR22,BPPCT040,EPPCU9168,EPPCU0961)obtained a total of 38 observe alleles from the Cerasus,with an average of 3.8 observed alleles per locus.The effective allele,Shannon polymorphism information index,observed heterozygosity,expected heterozygosity,unbiased expected heterozygosity and fixed index were 2.937,1.121,0.504,0.627,0.648,and 0.160,which could be inherited as Cerasus effective molecular markers for diversity analysis.Cerasus are highly evolved plants in phylogenetic evolution.In the process of differentiation of vessel element,various traits are not synchronized in phylogenetic evolution,and their individual development process repeat the phylogenetic process.The 10 pairs of SSR primers designed and synthesized for the genetic diversity of Cerasus showed polymorphism,which were suitable for the identification and genetic diversity analysis of Cerasus.