耐盐菌对盐胁迫下水稻种子萌发及幼苗生长的影响

土壤盐渍化严重影响植物生长发育,为探讨微生物对盐胁迫下植物种子萌发及幼苗生长的调控作用,以宁粳28号水稻种子为材料,采用培养皿滤纸萌发的方法研究不同耐盐菌株组合对150 mmol·L^-1 NaCl胁迫下与水稻种子萌发及幼苗生长相关的生理代谢的影响。结果表明:不同菌株组合对盐胁迫下水稻种子萌发及幼苗生长均有一定的促进作用。与盐胁迫下不加菌的对照处理相比,枯草芽孢杆菌+苏云金芽孢杆菌+阿氏芽孢杆菌(ABD)和枯草芽孢杆菌+苏云金芽孢杆菌+多黏类芽孢杆菌+阿氏芽孢杆菌(ABCD)菌株组合可使发芽率提高约20%,ABCD组合使水稻芽长和根长分别提高4.75倍和0.72倍,种子活力指数提高3.19倍,幼苗耐盐指数提高3.20倍,叶绿素含量与根系活力均显著增加(P<0.05),相对盐害率显著下降(P<0.05)。菌株组合不同程度地降低了盐胁迫下水稻幼苗丙二醛(MDA)含量,提高了过氧化物酶(POD)、过氧化氢酶(CAT)及超氧化物歧化酶(SOD)活性,可缓解盐分对水稻造成的毒害,但各处理之间存在一定的差异,其中多菌株复配能较好地提高幼苗SOD活性。研究表明,耐盐微生物能够增强水稻耐盐性,促进水稻种子萌发及幼苗生长,多菌株复配效果优于单菌株。

Effects of salt-tolerant bacteria on rice seed germination and seedling growth under salt stress

Soil salinization seriously affects plant growth and development. To explore the effects of microorganisms on seed germination and seedling growth under salt stress, filter paper germination of Ningjing 28 seeds in a petri dish under 150 mmol·L^-1 NaCl stress was conducted to study the effects of different salt-tolerant strain combinations on seed germination and seedling growth according to the physiological metabolism of rice. The results showed that different strain combinations promoted rice seed germination and seedling growth under salt stress. Taking no bacteria under salt stress as the control, the combinations of Bacillus subtilis + Bacillus thuringiensis + Bacillus aryabhattai(ABD) and Bacillus subtilis + Bacillus thuringiensis + Paenibacillus polymyxa + Bacillus aryabhattai(ABCD) could increase the germination rate by approximately 20%. The ABCD combination increased the bud length and root length by 4.75 times and 0.72 times, respectively, seed vigor index by 3.19 times, and salt tolerance index by 3.20 times. The chlorophyll content and root vigor also significantly increased(P<0.05), whereas the relative salt injury rate significantly decreased(P<0.05). The combination of strains reduced the content of malondialdehyde(MDA), increased the activities of peroxidase(POD), catalase(CAT), and superoxide dismutase(SOD) in rice seedlings under salt stress, and alleviated the salt toxicity to rice. There were some differences among the treatments, and the combination of multiple strains could improve the activity of SOD in rice seedlings. Salt-tolerant microorganisms can enhance the salt tolerance and promote the seed germination and seedling growth of rice. Moreover, the effect of multiple strains is better than that of a single strain.