Differences In Ecological Characteristics Of Different Genotypes Of Leymus Chinensis And The Effects Of Genotypic Diversity On Community Function

In recent years,due to the impact of human activities on the global environment,the ecological environment has been severely damaged,leading to a sharp decline in biodiversity,and the ecological consequences have also received wide attention.The relationship between biodiversity and ecosystem functions has received increasing attention.But these studies were focused on the species diversity level.Genotypic diversity is a key level of biodiversity.Studies have shown that genotypic diversity can also have important effects on the ecosystem functions.Such as genotypic diversity can increase productivity,accelerate recovery after interference,and increase resistance to interference and so on.However,the mechanism is not yet clear,and it is worth our deeper research.Leymus chinensis is one of the most important dominant species or constructive species in the Northeast China and Inner Mongolia grasslands.Due to the widespread distribution of Leymus chinensis and its strong ecological adaptability,different genotype populations have formed in the long-term adaptation to the environment.This study used Leymus chinensis of 12 different genotypes were used as the experimental material.We measured the ecological characteristic index of Leymus chinensis of 12 different genotypes and comparised the ecological characteristic of Leymus chinensis of different genotypes.At the same time,by controlling the number of genotypes in Leymus chinensis population,five genotypic diversity levels were set for Leymus chinensis population,namely,one genotype level,2,4,8 and 12-genotypic diversity level.And basing on the measurement and analysis of Leymus chinensis biomass,community nutrients,reproductive allocation,weed diversity,soil nutrient content at each level of genotypic diversity,we preliminary discussed the effects of genotypic diversity on community ecological function.The main results is the following:(1)Studies on the ecological characteristics of different genotypes of Leymus chinensis showed that there were a significant differences in the number,number of shoots,total root length,seedling biomass,root biomass,and shoot biomass of different genotypes.The number and number of shoots 6 genotype were the highest,being 21.600 and 26.600 respectively.The number of seedlings of the 3 genetype was the lowest,it was 3.000,and the number of the 10-genotype was the least,which was 2.000.The root biomass and plant height of the 5 genotype were the highest,which were 5.694 g and 265.200 cm,respectively.2 Genotype had the shortest total root length and the least number of vegetative strains.The study on the asexual growth of different genotypes of Leymus chinensis has revealed that the 5 and 6 genotype have a relatively rapid asexual reproduction rate under sufficient space conditions.2 Genotype and 3 genotype have a relatively slow rate of asexual reproduction.The phenophases of different genotypes of Leymus chinensis were observed and the results showed that different phenotypes of Leymus chinensis had different phenological phases.The above results indicate that different genotypes of Leymus chinensis have different ecological characteristics during the long-term adaptation to the environment.Among them,the 5 and 6 genotype of Leymus chinensis have a relatively strong asexual ability to reproduce,2 and 3 genotypes of Leymus chinensis.asexual reproduction is relatively weak.(2)With the increase of genotypic diversity level,aboveground biomass,total underground biomass,total biomass,root-top ratio,0-10 cm underground biomass of Leymus chinensis significantly increased,the genotypic diversity levels were all higher than those of the one genotype population.But there was no significant difference of 10-20 cm,20-30 cm underground biomass.The result indicates that the level of genotypic diversity in Leymus chinensis affects primary productivity,and genotypic diversity can improve the primary productivity.(3)The height,ploret number,grain number,grain weight,reproductive allocation?,reproductive allocation? and seed setting rate of the individual strains of Leymus chinensis were significantly affected by genotypic diversity.But there were no significant difference in the length of the spike,weight of spike,weight of plant,floret number,percentage of reproduction growth,reproductive allocation?of individual Leymus chinensis.In the community level,with the increase of genotypic diversity level,the 1000-grain weight was decreased;the 12 genotypic diversity level of 1000-grain weight was significant lower than one genotype population.But the percentage of reproduction strains,reproduction allocation had no significant difference among different level of genotypic diversity.This indicated that the level of genotypic diversity had significant effect on the reproduction.(4)With the increase of genotypic diversity level,weed biomass,Patrick richness index,Gleason richness index,Shannon-weinner information index,Simpsom index and Pielou evenness index showed decreasing trends,but the weed biomass,Shannon-weinner information index,Shannon-weinner information index and Pielou evenness index did not differ significantly.With the increase of genotypic diversity level,weed richness and evenness decreased.It indicated that genotypeic diversity can decreasePatrick richness index and Gleason richness index.(5)The level of genotypic diversity had no significant effect on the nitrate nitrogen,ammonium nitrogen and total nitrogen of the community.There was no significant difference in the community nutrient levels between different genotype levels.This indicated that the level of genotypice diversity had no significant effect on the community nutrient.There was no significant difference anong different genotypic diversity of soil organic carbon content and total nitrogen content.However,with the increase of genotypic diversity level,the 20-30 cm soil total phosphorus content had decreased.The 20-30 cm soil total phosphorus content of one genotype was significant higher than 4 genotypic diversity and 8 genotypic diversity.(6)The different phenophases of different genntypic diversity levels of Leymus chinensis were different,and the level of genotypic diversity was significantly correlated with the Leymus chinensis fruit ripening period,the yellow dry period and the total growing period.But there were no significant correlation between the vegetative period,flowering stage post-fruit nutrition and the level of genotypic diversity.Synthesize the above results,ecological charateristics of Leymus chinensis of different genotypes were significantly different.The increase in Leymus chinensis genotypic diversity could improve primary productivity of populations,affect reproduction allocation,decrease weed diversity,influence the phenophases.But genotypic diversity had on significant influence on community nutrient,the soil nutrient content.The results will provide scientific theoretical guidance for the protection and rational utilization of Leymus chinensis grassland in the future.