Effects Of Nitrogen Deposition And Nutrient Addition On Genetic Diversity Of Stipa Baicalensis Population

It is the basic content of ecology to reveal the genetic effect of habitat heterogeneity and the micro-evolution process of local population.In this paper,IS SR molecular marker technique were used to analyzed the genetic diversity and genetic structure of Stipa baicalensis under the condition of simulated nitrogen deposition and nutrient addition in Inner Mongolia meadow steppe,to explore the effect of nitrogen deposition on the genetic diversity of S.baicalensis population and to reveal the genetic diversity and environmental factors of relevance population.This study was helpful to reveal the effects of habitat heterogeneity at different scales on the genetic pattern of S.baicalensis,the micro-evolution process of S.baicalensis and the effect of global change on its genetic diversity.The main research results are as follows:1 S.baicalensis has rich genetic diversity.Nutrient added 3 years later,S.baicalensis at the species level,polymorphic loci was 98.44%,the genetic diversity index Nei’s index and Shannon’s index were 0.2784 and 0.4299,respectively.After six years,the percentage of polymorphic loci in S.baicalensis was 100%,Nei’s index and Shannon’s index were 0.2828 and 0.4356,respectively,which all increased in varying degrees.2 The addition of N2(5.0g/m~2/a)and N(10.0g/m~2/a)nitrogen fertilizer increased the genetic diversity of S.baicalensis and adding N1(2.5 g/m~2/a)genetic diversity inhibited the genetic diversity of S.baicalensis,genetic diversity increases with increasing nitrogen concentration;long-term addition of N1,N2 and N three levels of nitrogen fertilizer all can promote the genetic diversity of S.baicalensis population,and with the increasing of nitrogen concentration showed a tendency to climb up and then decline,the highest genetic diversity is 5.0g/m~2/a,adding three nitrogen concentration and sort of CK are N2(5.0)>N(10.0)>N1(2.5)>CK.3 Short-term and long-term addition of Phosphate fertilizer had inhibitory effects on the genetic diversity of S.baicalensis.The addition of nitrogen and phosphorus mixed fertilizer(10.0gN+10.0P/m~2/a)could promote the genetic diversity of S.baicalensis,but the effect is not as good as adding nitrogen fertilizer alone;with the increase of the number of years to add fattening,the genetic diversity of S.baicalensis was compared with CK,N>NP>CK>P.4 Habitat heterogeneity caused by small-scale nutrients additions changed the g enetic differentiation structure of S.baicalensis population,different nitrogen co ncentrations and different nutrient types have different effects on them,indicati ng that S.baicalensis is more sensitive to the change of environmental factors,changes in spatial heterogeneity caused by the added nutrients is an important reason for Stipa produce genetic differentiation.