Study On The Dynamic Characteristics Of Amino Sugar And Microbial Biomass In Leaves During The Decomposition Of Quercus Wutaishanica Litter

The litter decomposition is the main way of ecosystem material circulation and energy conversion,which provides energy for microbial growth,provides nutrients for plant growth,affects carbon storage of ecosystems,and affects global climate change.Current studies have shown that the decomposition process of litter is mainly caused by microorganism,but the changes of microbial biomass and its cell wall residues during the litter decomposition are not clear.Therefore,we study the microbial biomass and its products in the process of litter decomposition,focusing on the changes of microbial biomass and the amino sugars of microbial cell wall residues during the decomposition of litter.To analyze the effects of environmental factors on the eco-stoichiometric characteristics of litter microorganism biomass and the effect of litter amino sugar in the decomposition process of litter.This paper attempts to elucidate the relationship between the environmental factor driving-substrate availability and the change of substrate quality-the litter microorganism biomass and its ecological stoichiometric metering characteristic adjustment-litter amino sugar content decomposition/accumulation and its interaction relationship in the decomposition process of litter.To define the dynamic characteristics of microbial cell wall product amino sugars in the process of decomposition of litter,and to regulate process of microbial biomass ecological stoichiometric metering characteristics.In order to further understand the process and mechanism of microorganism during the decomposition of litter,and enrich the theory of the decomposition process of litter.The research results show that:1.In the process of litter decomposition,the correlation between the microbial biomass and the water content of the litter was changed in the order of LMBC(litter microbial biomass carbon)< LMBN(litter microbial biomass nitrogen)< LMBP(litter microbial biomass phosphorus),the correlation coefficient was 0.38,0.59,0.74,respectively,and the content of microbial biomass P of the litter was significantly affected by litter water content.The microbial biomass content of the litter was significantly affected by seasonal variation,decomposition gram number and placement level,in which the changes in moisture and temperature conditions caused by seasonal changes were the main factors that caused the change of microbial biomass in the litter.The maximum value of the content of C and N of microbial biomass in the litter appeared in September,while the maximum value of the microbial biomass P content of the litter was in October,which showed hysteresis effect,and the temporal and spatial variation of microbial biomass C,N and P in the litter was not synchronized.2.The change of water content affects the ecological stoichiometric characteristics of microbial biomass of litter,especially for the C:P and N:P of microbial biomass,and the fluctuation of phosphorus content of microbial biomass is the main factor causing the C:P and N:P variation of microbial biomass in the litter.The change of the season and the gram number significantly affected the microbial biomass and its ecological stoichiometric characteristics,and the decomposition bag placement level had no effect on the ecological stoichiometric characteristics of the microbial biomass of the litter.The plasticity of ecological stoichiometric characteristics of microbial biomass in the litter,the ecological stoichiometric characteristics of microbial biomass in the litter was different under the condition of water content of different litter,and the steady state characteristics were presented under the condition of high water content,and the unsteady characteristics were presented under low water content.3.During the decomposition of litter,the content of amino mannose was significantly higher than that of galactosamine in the soil,which showed that the content of galactosamine was significantly higher than that of mannosamine.The ratio of glucosamine/ muramic acid to the C:N of litter was consistent in the process of decomposition of litter.The changes of microbial community structure during the decomposition of litter were reflected,and the initial fungal dominance gradually changed to the dominant bacterium,and the muramic acid of the remnant material of the bacterial cells accumulated continuously with the decomposition.In the process of litter decomposition,glucosamine and muramic acid can be used as carbon source and nitrogen source in the demand of microorganisms,while the accumulation and decomposition of amino sugars occur simultaneously,and the accumulation/decomposition of amino sugars depends on which process dominates.The content of amino sugar was higher than that of soil,and the total amount of amino sugar increased gradually with the decomposition of withered deciduous leaf,which reflected the gradual accumulation of microbial cell wall products in the litter system.4.The effects of environmental factors(moisture and temperature)on the microbial biomass and the ecological stoichiometric characteristics of litter were more powerful than the basic physicochemical properties(soluble carbon,nitrogen,phosphorus,etc.)of litter leaves.The basic properties of litter and environmental factors explained the variation of 4.28% and 12.16%,respectively,and the change of water content of litter was the main influencing factor,the interaction between them explained 42.28%.The effects of environmental factors on the content of amino sugars in the litter during the decomposition of litter were slightly stronger than the basic physicochemical properties of litter,and the change of temperature was the main influencing factor.The interaction between the two explains that 21.09% of the variance is greater than the effect of environmental factors and the basic physical and chemical properties of the litter.As an important carbon source and nitrogen source,amino sugars are decomposed in the process of litter decomposition to maintain the balance of ecological and chemical characteristics of microbial body,so that microbial biomass C:N maintain basic stable homeostasis.The decomposition/accumulation dynamic equilibrium of amino sugar content in litter was dominated by the combination of water temperature condition-substrate nutrient availability and substrate quality-microbial biomass and its ecological stoichiometric characteristics,and its interaction promoted the decomposition of litter.