Genetic Diversity And Adaption Mechanisms Of Leaf Color Cline Of Leymus Chinensis Under Heterogeneous Habitats

Leymus chinensis was the main constructive species or dominant species in our country northern grasslands.L.chinensis populations that different leaf color setted mosaic distribution,constituted leaf color cline under natural grassland,leaf color gradient was associated with genetic variation,and the main ecological factor analysis of cline formation was still lack of system research.This paper used ISSR molecular marker technology and no quadrat sampling method,we synthetically studied genetic diversity,phenotypic diversity and dominant influence factors of L.chinensis leaf color cline under different soil types of Chang Ling,Gu Yuan and Tu Mu-ji natural grasslands,this paper revealed that genetic variation law and evolutionary relationship of L.chinensis leaf color cline,enriched research system of cline,provided theoretical basis for new varieties the breeding of L.chinensis.The research of genetic diversity showed that:it had obtained clear,good repeatability and high polymorphism with 19 primers were selected from 21 ISSR primers.Genetic diversity was the largest of gray-green L.chinensis,and the least of yellow-green L.chinensis in Chang Ling:genetic diversity was the largest of color transition L.chinensis,and the least of second yellow-green L.chinensis in Tu Mu-ji and Gu Yuan.It had greater genetic diversity of L.chinensis leaf color cline in Chang Ling than Tu Mu-ji and Gu Yuan.Genetic diversity of L.chinensis in Chang Ling:sandy soil>meadow soil>saline soil;genetic diversity of L.chinensis in Tu Mu-ji:saline soil>chestnut soil;genetic diversity of L.chinensis in Tu Mu-ji:chestnut soil>meadow soil.Between different leaf color and different soil types of L.chinensis populations in the same area,genetic diversity within populations was greater than among populations.It had a wealth genetic variation of L.chinensis leaf color cline.Nm was the largest of gray-green and sandy soils L.chinensis populations in Chang Ling,and color transition and chestnut soils L.chinensis populations in Gu Yuan and Tu Mu-ji.Nm of L.chinensis populations:Chang Ling area>Gu Yuan area>Tu Mu-ji area.L.chinensis leaf color cline:Nm<1,Gst>0.4158,Gst was the largest of yellow-green L.chinensis in Chang Ling,and second yellow-green L.chinensis in Tu Mu-ji and Gu Yuan,the results showed that it had already differentiated of different leaf color L.chinensis populations,differentiation was mainly caused by genetic drift.Regression analysis showed that the chlorophyll index of L.chinensis leaf color cline and 20 allele frequency with linear regression relationship under different habitat conditions,reached significant or very significant level.Allele frequency change of site-specific was the genetic basis of effect chlorophyll index changes.Analysis showed that the evolutionary relationship of L.chinensis leaf color cline:in addition to the fourth sample material of gray-green L.chinensis in Chang Ling area meadow soils,10 individuals of each leaf color type were gathered for an independent branch,and had a higher approval rating;firstly five color of the same soil types in different areas were gathered for a branch,formed a evolution unit,and had a higher approval rating;Different leaf color Lchinensis in binary branches way evolution,gray-green or yellow-green L.chinensis was always the first differentiation out from the type;gene flow was smaller among populations in different soil types of different areas(Nm<0.7204),leaf color differentiation was mainly caused by genetic drift,different drift strength was produced by different environmental pressure,formed differentiation process of different leaf color phenotypes,leaf differentiation of L.chinensis populations in different habitats had the similar results that formed the similar differentiation of phenotype of different leaf color,with process of parallel evolution,that the population carried on the evolutionary history of individual independent but the results similar in different soil types,climatic conditions and survival pressure,evolved the similar different leaf color type of L.chinensis to adapt the different environmental pressure.The research of phenotypic diversity showed that:it reached significant or very significant related level that CB and Na,Ne,H./,Ht,H of L.chinensis leaf color cline in Chang Ling area meadow soils;C1,CA+B,CA and Ne of L.chinensis leaf color cline in Tu Mu-ji area saline soils.There was correlation between leaf index change of L.chinensis cline and change of genetic diversity.The change of leaf color indicators was mainly with changes of leaf and panicle of L.chinensis phenotype had an extremely important relationship,the most reached significant or very significant related level.Regression analysis showed that:the majority of indicators of phenotypic diversity of L.chinensis leaf color cline and the part of indicators of environmental factors,climatic factors with linear regression relation,reached significant or very significant level.And genetic diversity indicators of L.chinensis leaf color cline:Na,Hs,H,Ht and water content,Ne and water content and conductivity,I and water content and salinity in Chang Ling area;Ne and water content,H,I,Ht,Hs and organic matter content in Tu Mu-ji area;Na,Ne and conductivity in Gu Yuan area with linear regression relation,reached significant or very significant level,showed that phenotypic diversity of L.chinensis leaf color cline was mainly affected by the comprehensive effects of environmental factors and climate factors,but the genetic diversity:Chang Ling area was mainly affected by the comprehensive effects of soil moisture and soil salinity,Gu Yuan area was mainly affected by the soil salinity,and Tu Mu-ji area was affected by soil nutrients.