Functional Gene Diversity Of Ammonia-oxidizing Microbes Of Soil In Phyllostachys Pubescens.

Mao bamboo (phyllostachy pubescens), one of the major forest recourses in southern China, has been widely developed and its intensively managed area is increasing. Nitrogen is one of the key nutrition for bamboo growth since bamboo is an N-favorite species. Ammonium oxidation is one of the most important processes in nitrogen recycling,by which ammonia would be oxidized into nitrate. The objective of this thesis was to find out the characteristics and evolution of soil ammonium oxidation microorganisms (AOM) as well as anthropogenic effects by determent the communities and diversities of ammonium oxidation bacteria (AOB) and ammonium oxidation archaea (AOA) by means of PCR-DGGE and real-time PCR based on functional gene of AOM--amoA in natural and intensive management bamboo forest. The following main results were obtained:(1) With the invasion process of bamboo into natural broad leaved forest in the area of Tianmu Mountain National Natural Reserve, the soil chemical properties except from pH, total P and exchange K there ware no significant changes were measured. Soil AOB was sensitive to properties changes with only 2 types of AOB species existing in all the soil samples and low similarity between triple samples. While the opposite situation was true for AOA and there were 8 types AOA species existing in all the soil samples and relative higher similarity between triple samples.(2) With the invasion process of bamboo into Chinese fir forest in the area of Tianmu Mountain National Natural Reserve,the soil chemical properties except from organic matter and total N there ware no significant changes were measured. Soil AOB was sensitive to properties changes with only 2 types of AOB species existing in all the soil samples. There was low similarity between triple soil samples of Mao bamboo,however,many dominant species of AOB were generated. The opposite situation was true for AOA and there were 6 types AOA species existing in all the soil samples while many dominant species disappeared.(3) Soil under intensively managed bamboo forest by weeds cutting and fertilizing was rich in AOA diversity and detected 7 types of common species in all the soil samples. Soil AOA community was no quite different among the layers while each layer of soil has its own characteristic species. Intensive management of bamboo in this study did not result in significant changes in AOA communities and all the soil samples was clustered in one group with similarity value 0.55. The Evenness index were similar with each other except sample NO 1 (surface 0-10 cm soil under conventional practice). The results from real-time PCR indicated that the amoA copy numbers of surface soil decreased with increase of intensive time from 0 to 20 years, but return to the original level by the time of 30 years. Subsurface soil (10-30cm) has the similar trend with surface soil but the amoA copy numbers was larger in 30 years than 0 year bamboo stand. The amoA copy numbers was decreased with the depth except in 30-year bamboo stands.