Abstract: By the method of Biolog, a comparative study was made on the utilization level of single carbon source by the microbes in the rhizosphere soils of two
transgenic cottons and their parents, aimed to approach the effects of planting transgenic cotton on the functional diversity of rhizosphere soil microbial community. Compared with planting non-transgenic cotton, planting transgenic cotton had less effects on the carbon sourceng utilization ability, Shannon functional diversity index, and evenness index of rhizosphere soil microbes at seedling, squaring, boll-opening, and senescence stages, but decreased the carbon source utilization ability and functional diversity index at flowering and boll-forming stage significantly. Principal component analysis (PCA) indicated that there existed greater differentiation in the carbon source utilization by the microbes in rhizosphere soils of non-transgenic and transgenic cottons at flowering and boll-forming stage, suggesting the significant difference in the carbon source utilization pattern of the microbes at this stage.

Key words: rhizosphere soil, microbial community, Biolog, principal component analysis, arbuscular mycorrhizal fungi, heavy metal, tolerance, functional difference.