Model Analysis Of The Effect Of Genotype Diversity On Physiological Integration Of Leymus Chinensis Population Under Mowing

Leymus chinensis is one of the main constructive species in typical grasslands in northern China.Its distribution range is wide,and the differences of natural conditions and geographical environment in different regions lead to the formation of different genotypes of Leymus chinensis,and gradually form Leymus chinensis populations with different genotype diversity.Genotype diversity plays an important role in influencing community composition and structure,improving primary productivity of population,reducing disturbance and maintaining ecosystem stability.Leymus chinensis is a typical clonal rhizome plant.When one ramet is stressed,the other ramet will transport nutrients to the stressed ramet through the rhizome to support its growth,that is,physiological integration occurs.Cutting is a cultivation and utilization technique disturbed by human beings.Different cutting intensity will lead to corresponding changes in plant growth,productivity and regeneration ability.Three populations of Leymus chinensis with different genotypic diversity levels were constructed in this study,By analyzing the traits and biomass of Leymus chinensis under different genotype diversity levels,the physiological integration of Leymus chinensis after moderate and severe mowing,the response mechanism of genotype diversity to physiological integration under mowing treatments,and the relationship between genotype diversity and plant traits and productivity were studied.Here we come to the following results:(1)With the increase of genotype diversity,the number of plants,aboveground biomass,total tiller number,underground biomass and total biomass of Leymus chinensis population at the end of rhizome connection,rhizome cutting and non-cutting under 30% and 60% cutting treatments all showed an upward trend.Under the treatments of cutting 60% and cutting 30% at the three genotype levels,the number of Leymus chinensis plants,the total number of tillers,the underground biomass and the total biomass at the cutting end and the non-cutting end were higher than those under the rhizome cutting state.Under 60% cutting treatment at the three genotype levels,the number of Leymus chinensis plants,total tillers,aboveground biomass and total biomass at the cutting end and the non-cutting end were lower than those under the rhizome cutting state.Under 30% cutting treatment at genotype level,the aboveground biomass,underground biomass and total biomass of Leymus chinensis at cutting end and non-cutting end were higher than those under rhizome cutting.The total tiller number,plant number,aboveground biomass,underground biomass and total biomass of 30% cutting end of rhizome connection at genotype 1and 3 were significantly higher than those of 60% cutting end.At the three genotype levels,the underground biomass and total biomass of 30% cutting treatment at the uncut end of rhizome connection state were significantly higher than those of 60%cutting treatment.With the increase of genotype diversity,the plant height,stem length,stem biomass,leaf dry weight,leaf area,specific leaf area,aboveground biomass,underground biomass,root traits and other indicators at the cutting end and the non-cutting end under the conditions of rhizome connection and cutting under 30%and 60% cutting treatments all showed an upward trend.The above-ground biomass,underground biomass,plant height,stem biomass,leaf width,leaf dry weight,leaf area,rhizome biomass,fibrous root biomass,and root traits at the cutting end of the three genotype levels were higher than those at the rhizome cutting point under the30% and 60% cutting rhizome connection treatments.At the level of cutting 30% at the three genotypes,the plant height,stem biomass,specific leaf area,underground biomass,rhizome biomass and fibrous root biomass of the uncut ramet end under the rhizome connection treatment are lower than those under the rhizome cutting treatment;The plant height,stem biomass,stem length,underground biomass,aboveground biomass,rhizome biomass,root surface area and rhizome weight of the uncut ramets under the treatment of cutting 60% and rhizome at the level of the three genotypes are lower than those under the treatment of rhizome connection.The plant height,stem diameter,stem biomass,leaf area and underground biomass of 30%cutting end under rhizome connection treatment at three genotype levels were higher than those under 60% cutting treatment.At the three genotype levels,the specific leaf area,rhizome biomass and root surface area of 30% non-cutting end of rhizome connection treatment were higher than those of 60% cutting treatment [same as above].The increase of genotype diversity can enhance the physiological integration effect of Leymus chinensis population;Excessive cutting may inhibit the growth and development of Leymus chinensis;Physiological integration is helpful to alleviate the effect of cutting treatment on Leymus chinensis.(2)According to the decomposition formula of Loreau and Hector’s net diversity effect,56 of the net diversity effect values are positive.The 31 net effect values were significantly different from 0.In the results of the study,there are 21 response variables independently dominated by complementary effect(specifically]including aboveground biomass(3/6 genotype level,Rhizome connection mowing60%),aboveground biomass(3/6 genotype level,Rhizome cutting 60%),aboveground biomass(6 genotype level,Rhizome connection cutting 30%),aboveground biomass(6 genotype level,Rhizome cutting 30%),underground biomass(6 genotype level,Rhizome connection mowing 60%),underground biomass(6 genotype level,Rhizome cutting 60%),underground biomass(6 genotype level,Rhizome cutting and cutting 30%),total weight of rhizome(6 genotype level,Rhizome cutting and cutting 60%),total rhizome weight(6 genotype level,Rhizome connection mowing 60%),total rhizome weight(6 genotype level,The total weight of fibrous roots(3/6 genotype level,Rhizome connection mowing 60%),total fibrous root weight(3/6 genotype level,The total weight of fibrous roots(3 genotype level,Rhizome connection cutting 30%),total fibrous root weight(6 genotype level,Rhizome cutting and cutting 30%),number of plants(6 genotype level,The number of tillers(3/6 genotype level,Rhizome connection mowing 60%),tiller number(3/6genotype level,Rhizome cutting and cutting 60%),tiller number(3/6 genotype level,Rhizome cutting and cutting 30%),root-shoot ratio(3/6 genotype level,Rhizome connection mowing 60%),root-shoot ratio(3/6 genotype level,Rhizome cutting and cutting 60%),root-shoot ratio(3/6 genotype level,Rhizome connection mowing30%),root-shoot ratio(3/6 genotype level,Rhizome cutting and cutting 30%),there are three response variables independently dominated by selection effect [more specifically],underground biomass(3 genotype level,rhizome connecting cutting60%),total rhizome weight(3 genotype level,rhizome connecting cutting 60%),total rhizome weight(6 genotype level,rhizome connecting cutting 30%),total fibrous root weight(3 genotype level,rhizome connecting cutting 60%),tiller number(3genotype level,rhizome connecting cutting 60%).Only two response variables dominated by the two effects were total fibrous root weight(3 genotype level,60% of rhizome connection cutting)and tiller number(3 genotype level,60% of rhizome connection cutting).The results showed that the effect of genotype diversity on physiological integration under mowing treatment was dominated by the complementary effect among different genotypes.(3)By establishing the structural equation of the relationship between genotype diversity,Leymus chinensis traits and aboveground biomass,To explore the influence of genotype diversity on aboveground biomass,The results showed that under the physiological integration of mowing treatment,there were two ways for the genotype diversity of Leymus chinensis and the influence of Leymus chinensis traits on aboveground biomass,One genotype diversity can directly affect aboveground biomass,while the other genotype diversity can indirectly affect aboveground biomass through the interaction among stem length,leaf area,stem biomass and dry leaf weight per plant.The study provides theoretical support for the relationship between genotype,traits and productivity of Leymus chinensis under physiological integration,and it is also of great significance to deeply understand the influence of ecological function on the rational utilization of Leymus chinensis community.