Abstract: In order to understand the effects of planting transgenic soybean on the nitrogen-fixing bacteria in rhizosphere soil, PCR-DGGE was used to study the molecular diversity of nifH genes in the plots planted with transgenic soybean, parent non-transgenic soybean, and local soybean. The sequences showed that low GC Firmicutes were on the top of the DGGE gel, and were significantly affected by sampling date. Chlorobi were not affected by either sampling date or soybean variety. Among the 46 sequences, 28 sequences were of Proteobacteria, occupying 60.8% of the total and showing in all area of the DGGE gel, and most of them were stable, not affected by sampling date or soybean variety. No significant differences were observed in the diversity of nitrogen-fixing bacteria in rhizosphere soils among the treatments of planting transgenic soybean, parent non-transgenic soybean, and local soybean at different sampling dates, suggesting that planting transgenic soybean had less effects on the diversity of nitrogen-fixing bacteria in rhizosphere soil.

Key words: Fraxinus mandchurica, Phosphorus stress, Chlorophyll biosynthesis, Photosynthesis, Biomass partitioning