[Community structure and its dynamics of phosphobacteria in Cerasus sachalinensis rhizosphere and nonrhizosphere]

By using selective culture media, the phosphobacteria in Cerasus sachalinensis rhizosphere and nonrhizosphere were isolated and identified, with their community structure and dynamics studied. The phosphobacteria isolated from three test substrates belonged to 13 genera, and Bacillus, Pseudomonas and Serratia were the main ones. The substrate added with slag was most suitable for the growth of phosphobacteria, on which, phosphobacteria had the highest population number but the lowest diversity index. There was a difference in the population number of phosphobacteria in rhizosphere and nonrhizosphere during the growth period of C. sachalinensis. In rhizosphere, phosphobacteria had the highest number (6 genera) in withhold-growing period of shoot, less in fast growing period of shoot and in defoliation period, and the least in germination period. The diversity index of phosphobacteria in rhizosphere also varied with the growth period of C. sachalinensis, which was in the order of fast growing period of shoot > defoliation period > withhold-growing period of shoot. In nonrhizosphere, the population number and diversity index of phosphobacteria had a decreasing trend with the growth of C. sachalinensis. All of these indicated that there was an obvious rhizosphere effect on phosphobacteria.