The Decomposition Of Triarrhena Lutarioriparia And Carex Cineraseens Litter And Dynamic Change Of Microbial Community In The Wetland Of Nanjishan

Litter is defined as the plant component that landing to the ground, as the resource of disintegtator’s material and energy, maintaining the biological function of ecosystem. It is the research hotspot of wetland ecosystem. Two typical plant litters of Poyang Lake, Triarrehena lutarioriparia(T.lutarioriparia) and Carex cineraseens (C.cineraseens) are discussed here. The microbial decomposition and its ecological significance are analyzed using litter bag technique. This thesis studied the microbial community diversity in two ways:non-additive effects in the decomposition of2010, dynamic change in the decomposition of2011. The biodiversity of microbial community is also studied.In this thesis, enzymology is studied by microplate fluorimetric assay. Fungal biomass is measured by HPLC. Total microbial DNA are extracted from litter samples, bacterial16S rDNA and fungal18S rDNA fragments are amplified by PCR, microbial communities are separated into single microbial population to build the microbial community diversity map by DGGE. Litter physiochemical parameters and microbial community diversity are correspondence analyzed. The results show as fellows.(1) After269d litter decomposition of2010, the bacterial community of mixed sample is closer to local plant bacterial community, the influence of plot is obvious. The decomposition rate, enzymology and bacterial diversity of mixed samples both showed non-additive effects. The T.lutarioriparia plot showed synergistic effect while the C.cineraseens plot showed retarded effect. Fungal community in two mixed litters both showed retarded response.(2) In2011, the decomposition of T.lutarioriparia is slow at first (0d-97d), and faster in later stage (127d-278d). The C.cineraseens litter decomposition rate is fast in early stage (0d-37d), and slow in later stage (127d-278d). After278d, the organic degradation rate of T.lutarioriparia and C.cineraseens was63.4%and64.5%respectively.(3) In2011, the enzymology of T.lutarioriparia litter is dominated by cellobiose and phosphatase in early stage (67d-97d), and lignin enzyme in later stage (245d), while C.cineraseens is just dominated by cellobiose and phosphorate enzymes in early stage (67d). Both T.lutarioriparia and C.cineraseens fungal biomass reached maximum on127d and lowest on245d.(4) The microbial cluster in2011is influenced by hydrology, there is one cluster before flooding (37d-127d), and another one after flooding (212d-278d). The correlation between microbial community, litter physicochemical parameters and exoenzyme is high. Bacterial diversity in T.lutarioriparia litter is gradually reduced over time, while gradually increased in C.cineraseens. But fungal community diversity is stable over time, and higher than bacteria both in T.lutarioriparia and C.cineraseens. So fungi is dominant in the decomposition of litter.