Community Structure Diversity Of Soil Microbes Under Phyllostachy Pubescens Stands Revealed By Plfas Analysis

Mao bamboo (phyllostachy pubescens) is one of the major forest resources in southern China. It has been widely developed by replacing natural forests such as broad leaved forest and masson pine forest, due to its high economic, social and ecological benefits. Soil microbes are the decomposers of ecosystem and play an important role in keeping ecosystem balance. However, as there are a large range of soil microbes and the habitat in which they live is very complicated, our knowledge about this versatile microbial community is very limited. The objective of this thesis was to find out the development of soil microbial community structure and microbial biomass under different types of bamboo systems, based on the phospholipid fatty acid (PLFA) analysis. The following main results were obtained:(1) By substitution of masson pine with bamboo, soil microbial biomass declined rapidly within 5 years (in short-term), but recovered gradually with the increase of bamboo cultivation history, and reached the similar level with masson pine after 25 years cultivation. Soil microbial communities in masson pine forest were significantly different with those in bamboo forest revealed from Statistical analysis based on PLFAs profiles. Soil microbial communities in bamboo stand established in 2002 was dissimilar with those in the rest of bamboo stands. and were more close to those in masson pine forest.(2) With the invasion process of bamboo into natural forest in the area of Tianmu Mountain National Natural Reserve, the soil total PLFAs and microbial community structure changed, but the three large microbes were relatively stable. With the invasion process of bamboo into coniferous forest, total PLFAs declined firstly and increased after, and 38.99% of total PLFAs increase. With the invasion process of bamboo into broad-leaved forest, total PLFAs always increased, the adding is 65.73%. Overall, after the replacement, the bamboo forest finally had more soil total PLFAs than pure forests, and ultimate bamboos microbial community structure is similar.(3) Intensive management including under brush and weeds removal, and successive fertilize application, leads to the decline of soil total PLFAs, which decresed by 67.8% within 30 years. Meanwhile, soil microbial community structures were obviously changed.(4) Through the analysis of soil microbial community structure and diversity after adding different quantity of bamboo leaf and incubating time , no obvious difference was observed for soil microbial biomass after 20-week incubation, but the number of PLFA and structure of soil microbial community were diverse under the different disposals and incubation times.The diversity index and evenness index showed no significant differences, but they had some change, which was increase firstly and then decline, where more bamboo leaf adding were higher than less ones.