| Leymus chinensis is one of the main dominant species and constructive species in the typical grassland of North China,which has important ecological and economic value.As a typical rhizome type clonal plant,Leymus chinensis can produce physiological integration after being disturbed,so that the connected clonal ramets can obtain enough resources from the adjacent ramets,so as to reduce the adverse impact of local environment.Because of the wide distribution of Leymus chinensis and obvious habitat differences,different genotypes of Leymus chinensis population were formed in the process of adapting to the environment.Genotype diversity can promote the productivity of plants,enhance the anti-interference ability of plants,and alleviate the harm of external interference to plants.Mowing,as a kind of artificial interference cultivation and utilization technology,can not only affect the individual characteristics of forage,but also affect the productivity of grassland community.However,the mechanism of the effect of genotype diversity on the physiological integration of Leymus chinensis under cutting interference is not clear.Therefore,we need more in-depth research in order to provide a scientific basis for the rational use of Leymus chinensis grassland.In this experiment,9 different genotypes of Leymus chinensiswere selected and 4 genotypic diversity levels,i.e.1,3,6 and 9,were designed.In order to further study the effect of genotype diversity on the physiological integration of Leymus chinensis under cutting interference,the biomass,individual characters and nutritional indexes of mowed and uncut ramets were studied.The results are as follows:(1)With the increase of genotypic diversity level,the number,total biomass and plant height of mowed and uncut Leymus chinensis and the total biomass of Leymus chinensis ramets to population increased first and then decreased under the conditions of 30%,60%,30% and 60% of rhizome cutting,and reached the maximum value under the level of 6 genotypic diversity.Under the condition of 1,3,6 and 9 genotype diversity level rhizome connection and 1,3,6 and 9 genotype diversity level rhizomes cutting,the number,total biomass and plant height of Leymus chinensis under 60% cutting treatment were lower than those under 30% cutting treatment.The total biomass of Leymus chinensis under the treatment of 30% and 60% genotypes diversity of 1,3,6 and 9 was higher than that under the treatment of rhizome cutting.The total biomass and plant height of Leymus chinensis at the level of 1,3,6 and 9 genotype diversity were higher than those at the level of rhizome cutting.At the same time,the number of ramets,total biomass and plant height of 1,3,6 and 9 genotypes were higher under 30% cutting than under cutting.However,at the level of 1,3,6 and 9 genotype diversity,the number of ramets,total biomass and plant height of the uncut Leymus chinensis were lower under the condition of rhizome connection than those under the condition of rhizome cutting.(2)With the increase of genotypic diversity,the height,stem length,stem diameter,stem biomass,leaf number,total leaf biomass,aboveground biomass,single leaf length,single leaf width,single leaf thickness and single leaf biomass of Leymus chinensis were measured under the conditions of 30%,60%,30% and 60% respectively The amount and area of single leaf increased first and then decreased.The height,stem length,stem diameter,stem biomass,leaf number and aboveground biomass of Aneurolepidium chinense were the highest at the level of 6 genotypic diversity.The plant height,stem length,stem diameter,stem biomass,leaf number,total leaf biomass and aboveground biomass of Leymus chinensis were higher than those of 60% cutting treatment at the level of 1,3,6 and 9 genotype diversity at the level of rhizome connection and 30% cutting treatment.At the level of 1,3,6 and 9 genotypes diversity,the height,stem length,stem diameter,stem biomass,leaf number,total leaf biomass,aboveground biomass,leaf length and leaf area of the mowed and 60% mowed Leymus chinensis were higher than those of the mowed.At the level of 1,3,6 and 9 genotype diversity,the width,thickness,biomass and specific leaf area of cutting ramet,stem biomass,leaf number,total leaf biomass,aboveground biomass,thickness and specific leaf area of cutting ramet were higher than those of cutting rhizome.However,under 60% cutting of genotypes 1,3,6 and 9,the stem diameter,single leaf length,single leaf width,single leaf biomass and single leaf area of Leymus chinensis under the condition of rhizome connection were lower than those under the condition of rhizome cutting.(3)With the increase of genotypic diversity level,the organic carbon content and total nitrogen content of Leymus chinensis increased first and then decreased,and reached the maximum value at the level of 6 genotypic diversity.Under the treatment of 1,3,6 and 9 genotype diversity level rhizome connection and 1,3,6 and 9 genotype diversity level rhizomes cutting,the content of organic carbon and total nitrogen in the cutting end and the uncut end of Leymus chinensis were lower than that of the cutting 30%.Under the condition of 60% cutting at the level of 1,3,6 and 9 genotypes diversity and 30% cutting at the level of 1,3,6 and 9 genotypes diversity,the content of organic carbon at the ends of uncut ramets under rhizome connection was lower than that under rhizome cutting.However,under the condition of 30% cutting at the level of 1,3,6 and 9 genotype diversity and 60% cutting at the level of 1,3,6 and 9 genotype diversity,the content of organic carbon and total nitrogen at the cutting end of Leymus chinensis was higher than that at the cutting end of rhizome.The above results showed that the increase of cutting intensity would reduce the growth of Leymus chinensis at the cutting branch end and the uncut branch end,while for the cutting branch end,the physiological integration could alleviate the damage caused by cutting at 30% and 60% treatments.The physiological integration could improve the growth of Leymus chinensis at 30% cutting intensity,but it could not make up for the effect of heavy cutting on Leymus chinensis at 60% cutting intensity.The increase of genotype diversity can improve the physiological integration of Leymus chinensis after being disturbed by cutting,and in this study,the level of 6 genotype diversity can greatly improve the physiological integration of Leymus chinensis after cutting The results will provide a scientific basis for the rational utilization and standardized management of Leymus chinensis grassland. |
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