转BADH基因大豆对盐碱土壤氮素转化的影响

以转甜菜碱醛脱氢酶(betaine aldehyde dehydrogenase)基因(BADH)大豆、非转基因亲本‘黑农35’、野生大豆、当地栽培种‘抗线王’、耐盐碱性较差品种‘合丰50’等5种大豆品种为材料,在典型盐碱土封闭种植,于大豆苗期、花荚期、鼓粒期和成熟期取根际土,采用经典方法测定氮素转化过程相关的细菌数量、生化功能及速效氮含量等指标的动态变化,为揭示转BADH基因大豆对土壤氮素转化的影响机制提供理论支持。结果表明:与非转基因亲本相比,转BADH基因大豆对苗期和花荚期根际土壤固氮菌数量有促进作用,但抑制苗期和花荚期根际土壤氨化细菌数量,对硝化细菌数量无显著性影响;显著促进成熟期大豆根际土壤固氮作用强度,对大豆苗期、花荚期和鼓粒期根际土壤氨化作用强度有显著抑制作用,显著促进各生育时期硝化作用强度;转BADH基因大豆苗期和花荚期根际土壤铵态氮含量显著降低,对鼓粒期根际土壤铵态氮含量无显著性影响,成熟期根际土壤铵态氮含量显著增高,大豆苗期、鼓粒期和成熟期根际土壤硝态氮含量显著升高,花荚期根际硝态氮含量显著降低。研究结果说明,转BADH基因大豆通过调节苗期、花期根际土壤氮素转化功能菌数量和生化过程强度进而影响氮素转化。

Effects of transgenic BADH soybean on nitrogen transformation in saline-alkaline soil

In this study, five cultivars of soybean, which were transgenic soybean by betaine aldehyde dehydrogenase (BADH) gene, non-transgenic parent 'Heinong35', wild soybean cultivar, local cultivar of 'Kangxianwang' and salt sensitive cultivar 'Hefeng 50', were planted in saline-alkali soil. The rhizospheric soil was sampled respectively at seeding stage, flowering and podding stage, pod-filling stage and maturity stage to determine (using classical methods) dynamic changes in bacteria population related to nitrogen transformation, biochemical function and available nitrogen contents. The results laid basic theory on the mechanisms of the effects of transgenic BADH soybean on nitrogen transformation. Compared with non-transgenic soybean, transgenic BADH soybean had positive effects on azotobacteria population and negative effects on ammonifying bacteria population at seedling, flowering and podding stages and with no significant effects on nitrifying bacteria population. Transgenic BADH soybean significantly increased nitrogen fixation intensity at maturity stage, and nitrification intensity at every growth stage of soybean. It also inhibited ammoniation intensity of soybean at seedling, flowering and podding, and pod-filling stages. The content of ammonium nitrogen in rhizospheric soils of transgenic BADH soybean was decreased compared with that of non-transgenic parent at seedling, flowering and podding stages. However, the content of ammonium nitrogen in rhizospheric soils with transgenic BADH soybean increased at maturity stage with no change at pod-filling stage. The content of nitrate nitrogen in rhizospheric soils of transgenic BADH soybean was higher than that of non-transgenic parent at seedling, pod-filling and maturity stages, and lower at flowering and podding stage. Transgenic BADH soybean influenced nitrogen transformation by changing the population of functional bacteria and the processes of biochemical intensity at seedling, flowering and podding stages.