NaCl胁迫下壳聚糖影响菜用大豆结瘤固氮的研究

Effect of Chitosan on Nodulation and Nitrogen Fixation of Vegetable Soybean under NaCl Stress

以蛭石为基质,以盐敏感品种“日本青”、耐盐品种“绿领八号”及其各自相匹配根瘤菌的共生体为研究对象,在人工气候箱中进行培养,50 mmol·L^(-1) NaCl胁迫处理下,研究不同浓度壳聚糖(CTS)处理对菜用大豆结瘤固氮的缓解效应。结果显示,NaCl胁迫下,CTS处理显著提高了2个品种菜用大豆生物量,根瘤数、根瘤鲜重及植株含氮量。壳聚糖能显著提高2个品种菜用大豆的根瘤豆血红蛋白含量、固氮酶活性以及根瘤细胞浆NH_(3)含量,降低了根瘤类菌体NH_(3)的含量。不同浓度CTS的诱导效果不同,200 mg·L^(-1)的CTS表现出了较强的促进作用,并且与“日本青”相比,“绿领八号”在该浓度下表现出明显的结瘤固氮优势,表明在NaCl胁迫下,CTS可以通过诱导菜用大豆根系的吸收能力,促进固氮酶的活性发挥,加速NH_(3)的转化,进而提高菜用大豆结瘤固氮能力。200 mg·L^(-1)是适宜的CTS处理浓度,该浓度下“绿领八号”具有较强的诱导潜力。

Using vermiculite as substrate,the symbionts of salt-sensitive cultivar“Nippon Green”and salt-tolerant cultivar“Lvling No.8”and their respective matching rhizobia were studied and cultivated in an artificial climate chamber.Under 50 mmol·L^(-1) NaCl stress,the alleviating effects of different concentrations of chitosan(CTS)on nodulation and nitrogen fixation of vegetable soybean were studied.The results showed that under NaCl stress,CTS treatment significantly increased the biomass,root nodule number,root nodule fresh weight and plant nitrogen content of the two soybean varieties.Chitosan could significantly increase the content of root nodule hemoglobin,nitrogenase activity and NH3 content of root nodule cytoplasm,and reduce the NH3 content of root nodule bacteria in the two vegetable soybean varieties.Different concentrations of CTS had different induction effects and 200 mg·L^(-1) CTS showed a strong promoting effect and“Lvling No.8”showed an obvious advantages in nodulation and nitrogen fixation at this concentration compared with“Nippon Green”,indicating that under NaCl stress,CTS could promote the nitrogenase activity by inducing the absorption capacity of vegetable soybean roots.It can accelerate the transformation of NH3 and improve the nodulation and nitrogen fixation capacity of vegetable soybean.200 mg·L^(-1) was the suitable CTS treatment concentration,under this concentration“Lvling No.8”had strong induction potential.