Effect Of Genotype Diversity On Age Structure And Bud Bank Of Leymus Chinensis Population

In recent years,with the aggravation of global climate change and frequent human activities,the number of plant population has been reduced,and the loss of plant genetic diversity has been intensified,which has a negative impact on the ecosystem.Therefore,the study of genetic diversity has been widely concerned by scholars at home and abroad.It has been found that the genotype diversity of dominant species has a significant impact on the poor environment and the single ecosystem function of community composition.As an important part of genetic diversity,genotype diversity can measure the ecological role.Therefore,the study of genotype diversity can provide an important theoretical basis for the maintenance and development of dominant species and ecological restoration of degraded populations.Leymus chinensis is a typical Rhizome Grass,which is widely distributed in the east of Inner Mongolia and the west of Northeast China.In the natural environment,there are differences in the number and species of genotypes among different populations of L.chinensis in different habitats,and then different populations with different levels of genotypic diversity are produced.In order to explore the ecological role of genotypic diversity in L.chinensis population,this study took L.chinensis as the research object,set up five genotypic diversity level control plots,and carried out the research on the influence of genotypic diversity on the age structure and bud Bank of L.chinensis population.The main results are as follows:The effect of genotype diversity on tiller number and biomass characteristics of L.chinensis population is mainly reflected in the young ramets.With the increase of genotype diversity level,the number and biomass of tiller plants in L.chinensis population 2a increased significantly in 2018(P < 0.05);while in 2019,with the increase of genotype diversity level,the number and biomass of tiller plants in 1a increased significantly(P < 0.05).The number and biomass of tillers increased in two years,but not significantly.Under the five genotypic diversity levels,the number of tillers and the age structure of biomass in 2018 were the highest in 1a or 2a,showingthe age structure of growth type or stable type;with the increase of genotypic diversity level,the age structure of the number of tillers and biomass of L.chinensis population transited from growth type to stable type,and the number of tillers and the age structure of biomass in 2019 The structure is growth type.The results showed that L.chinensis population put more energy and material into the formation and growth of low-age tillers,and less into the propagation strategy of old-age tillers.However,when the level of genotypic diversity is too high,the number and biomass of tillering plants in 4a of L.chinensis are higher than that of other genotypes.The effect of genotype diversity on the rhizome of L.chinensis population was significant.In 2018,with the increase of genotype diversity level,the rhizome length,biomass and dry matter accumulation of L.chinensis of all ages increased significantly(P < 0.01);in 2019 the rhizome length,biomass and dry matter accumulation of low ages L.chinensis of 1a and 2a increased significantly(P < 0.05),while the increase of other ages was not significant..In 2018,the age structure of rhizome length and biomass of L.chinensis population was the highest in 2a rhizome,showing a stable age structure.In 2019,the age structure of rhizome length and biomass was the growth type with the highest proportion of rhizome in 1a.The results of two years' experiment showed that the characteristics of 4a rhizome of 12 genotypes were higher than that of other genotypes.In the five genotypic diversity levels of L.chinensis population in two years,the proportion of buds in tillering node was the highest,and the tillering reproduction ability was strong.The age structure of buds was growth type,the proportion of 0a buds and 1a buds was the highest,and there was no 4a buds in 12 genotypes diversity level.The results showed that there were strong asexual reproduction ability in the five genotypic diversity levels of L.chinensis,and the reproduction and regeneration of the population were guaranteed.Genotypic diversity can make the population output more energy for future development in the young buds,and ensure the number of young active buds,so as to maintain the next stage of population development.To sum up,the number of tillers and rhizomes and the biomass characteristics of each age class increased with the appropriate genotype number,but the high genotypediversity would promote the increase of tillers and rhizomes of the old age class of L.chinensis population,and the population showed a declining signal.