Community And Diversity Of Ammonia-oxidizing Microbes In Four Major Types Of Forest In Subtropics Of China

The Broad-leaved forest,Chinese fir forest,Pinus massoniana forest and Bamboo grove are widelydistributed in subtropical area of southern China,Ammonium oxidation is one of the most importationprocesses in nitrogen recycling,by which ammonia would be oxidized into nitrate. The objective of thisthesis was to check the effects of different vegetation types on the community structures and diversitiesof ammonium oxidation microorganisms in subtropical forest ecological system by means ofPCR-DGGE and real-time PCR based on functional gene of ammonium oxidationmicroorganisms---amoA in two sites of Tianmu and Linglong mountain, and try to understanding thelinkage between soil microbes characteristics and soil N supply. The results will provide some guidesfor future forestation. The following main results were obtained:There were significant difference in soil pH, hydrolysable N and available K between differenttypes of forest in Tianmu Moutain, while no significant difference in soil organic C and available P havebeen measured. The bigger variations of soil properties under same forest have been observed. SoilAOB was sensitive to properties changes with only3types of AOB species existing in all the soilsamples and with lower similarity between triple samples. While the opposite situation was true forAOA and there were6types AOA species existing in all the soil samples and relative higher similaritybetween triple samples. There was no significant difference in diversities indictors of soil AOB andAOA community between four kinds of forest, soil AOB and AOA diversities under Chinese fir forestand Pinus massoniana forest were relative rich.There was no significant difference in soil chemical properties except from available K. Thevariations of soil properties under same forest were lower in Chinese fir and bamboo forest than those inBroad-leaved forest and Pinus massoniana forest with one sample being much bigger than the other twoduplications. Lower soil pH value were measured in Linglong Moutaian than those in TianmuMoutain. Since there were so small number of AOB in soils that we failed to get clear and DGGE PCRresults. Three types of AOA species existed in all the soil samples and also2,11and27were the basiccommon strips. A apparent dissimilarity of soil AOA Community Structure between triple samples wereobserved under Broad-leaved forest and Pinus massoniana forest, while the opposite situation was truefor Bamboo grove and Chinese fir forest. There was no significant difference in diversities indictors of soil AOA community between four kinds of forest, but a lower diversities being observed in bambooforest.The results released from real-time PCR indicated that there was no significant differences in AOBamoA copy numbers between four kinds of forest in Tianmu Moutain, while relative fewer copy numberwere detected in Bamboo grove and Chinese fir forest. There were significant difference in AOA amoAcopy numbers between forests, with the highest in Chinese fir forest, of which was significantly higherthan(p<0.05)those in Broad-leaved forest and Bamboo grove. There was no significant difference inAOB amoA copy numbers between four kinds of forest in Linglong Moutain, while relative more copynumber were detected in Bamboo grove. The opposite situation was true for AOA, soil AOA amoAcopy number under Chinese fir and Bamboo grove were significantly higher than (p<0.05)those in therest. Soil AOB amoA copy numbers in Linglong Moutain were about1-2orders of magnitude lowerthan those in Tianmu Moutain, however, AOA amoA copy numbers presenting a little higher(exceptPinus massoniana forest).