Effects Of Srts On The Nitrogen Transition And The Diversity Of AOB In Saline-Alkaline Soil

Salinization Resistance Transgenic Soybean (SRTS) was produced by using genetic engineering technology,which put Base aldehyde dehydrogenase gene(BADH) of beet into the cultivated soybean Heinong35.The Yield of SRTS planted in the enclosed area of Daqing-Anda was250-300kg/mu,but the risk and security of soil ecosystem by planting the genetically modified crops to farmland can not be ignored.As materials of the experiment, five genotypes’soybean including SRTS, the parent of SRTS (HN-35), the cultivated soybean variety Hefeng50(HF-50), Kangxianwang (K) and the wild soybean (Y-21) were compared in the study. The experiment were conducted in this study not only in order to investigate effects of Salinization Resistance Transgenic Soybean (SRTS) on the ammonia-oxidizing bacteria, nitrifying bacteria, ammoniation intensity, nitrification intensity, nitrogen fixation intensity, pH, available N and microbial biomass N in rhizospheric soil,but also study effects of Salinization Resistance Transgenic Soybean (SRTS) on the diversity of ammonia-oxidizing bacteria in rhizospheric soil by using molecular techniques polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE).Cultivation of SRTS could reduce the number of ammonia-oxidizing bacteria in rhizospheric soil.According to the average number of ammonia-oxidizing bacteria in the whole breeding time,the number of ammonia-oxidizing bacteria of SRTS was lower than HN-35and Y-21,but higher than K and HF-50.Compared with HN-35and Y-21.SRTS reduced the number of ammonia-oxidizing bacteria by9.66%and10.38%. SRTS had a significant impact on the number of nitrifying bacteria in rhizospheric soil.Compared with HF-50,K and Y-21,SRTS increased the number of nitrifying bacteria by25.47%,10.83%and8.13%.To a certain extent,SRTS could reduce the ammoniation intensity,but the influence was too small to reach the significant level.SRTS could increase the nitrification intensity.Compared with HN-35and other soybeans,SRTS was slightly higher than them.The planting of SRTS was significantly inhibited nitrogen fixation intensity. According to the average quantity of nitrogen fixation intensity in the whole breeding time,SRTS was lower than other soybeans.Compared with HF-50,K,Y-21and HN-35,SRTS was reduced45.22%,43.75%,37%and14.86%.SRTS could reduce pH and could increase available N and microbial biomass N in rhizospheric soil.During the whole breeding time,pH of SRTS and other soybeans were highest in Seedling Stage,which were between8.31to 8.41and lowest in Mature Stage,which were between7.20to7.90.The average amount of available N of SRTS was higher than other genotypes soybeans in the whole breeding time.The available N of SRTS was significantly higher than K and Y-21in Seedling Stage and was significantly higher than HN-35and Y-21in Filling stage.The average amount of microbial biomass N of different genotypes soybeans was SRTS> HN-35>HF-50>K> Y-21.DGGE fingerprint of AOB analysis results indicated that different genotypes soybeans had some similarity.Some bands were common to all. Compared to HN-35,SRTS appeared some missing bands, and also had some unique bands at the same time. The diversity analysis indicated that the number of bands of SRTS was higher than that of HF-50and Y-21; Shannon-Wiener diversity indexes (Dsh) related to ammonia-oxidizing bacteria (AOB) in SRTS rhizospheric soil was higher than HN-35and other soybeans;evenness indexes (Jsh) related to ammonia-oxidizing bacteria (AOB) in SRTS rhizospheric soil was just lower than HF-50,but significantly higher than those of near-isogenic counterparts (HN-35),K and Y-21.The cluster analysis showed that the similarity of HF-50and K was0.83which were in the same clusters,SRTS and HN-35was0.83which were in the same clusters.The similarity of Y-21,HF-50and K was0.51,while the similarity of SRTS,HN-35,Y-21,HF-50and K was only0.38.Our results indicated that SRTS increased the diversity of AOB, improved the uniformity of AOB and affected the growth and distribution of some groups of AOB in rhizospheric soil to some extent.