Bacillus amyloliquefaciens YM6对盐胁迫条件下玉米幼苗生理及生化的影响

Effects of Bacillus amyloliquefaciens YM6 on Physiological and Biochemical Characteristics of Maize under Salt Stress

为了解淀粉芽孢杆菌YM6菌株(Bacillus amyloliquefaciensYM6)对盐胁迫条件下玉米幼苗生理生化的影响,采用水培法培育玉米,水培营养液中含75 mmol/L NaCl作为盐胁迫条件,接种YM6后可以显著提高玉米耐盐能力。用透射电镜观察YM6菌株对盐胁迫下玉米幼苗根尖细胞核、线粒体、胞间连丝等组织结构的变化;利用微量法测定YM6菌株对玉米幼苗内超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)酶活;还测定玉米组织内过氧化氢(H2O2)、丙二醛(MDA)、脯氨酸(Pro)。结果表明:接种YM6菌株可有效缓解盐胁迫对玉米幼苗根尖亚细胞结构的损伤;与不接种对照组相比,玉米植株地上和地下组织内的H2O2质量分数显著降低(P<0.05);而Pro质量分数、SOD、CAT、POD活性均显著提高(P<0.05)。YM6菌株可通过提高玉米植株内抗氧化酶活性,降低氧化物质量分数以及提高Pro质量分数,从而缓解盐胁迫对玉米根尖细胞损伤,提高玉米对盐胁迫的耐受性。

To elucidate the effects of Bacillus amyloliquefaciens YM6 on the biochemical changes of maize under saline stress,YM6 was inoculated on maize seedlings grown in the nutrient solution containing 75 mmol/L NaCl.After 14 days cultivation,the biochemical characters of the enzymatic activities of SOD,POD and CAT,the content of H2O2,malondialdehyde(MDA)and proline were measured.The morphological characteristics of cell nucleus,mitochondria and cell membranes in maize root tips were examined by transmission electron microscope.The results indicated that cell morphologies,such as plasmolysis,damage of mitochondrial structure and nucleus structure,were altered because of the saline stress.Inoculation of YM6 could mitigate the cell damage by stress.The content of MDA and H2O2 decreased in both shoots and roots of maize plant treated with YM6,while the enzymatic activities of SOD,POD and CAT were increased.The proline content showed a significant increase under treatment of YM6,with maximum of 120.72μg/g dry mass.The current evidence indicated that the mechanisms of YM6 could enhance the activities of antioxidase system,lower the oxidant contents,increase the proline mass fraction,so as to relieve cellular damage of maize root tips caused by salt stress,finally,the maize tolerance to salt stress was increased.