Plant Biochemistry Laboratory, Department of Botany, University of North Bengal, Siliguri, 734013 West Bengal, India.
World J Microbiol Biotechnol. 2013 May;29(5):789-803. doi: 10.1007/s11274-012-1234-8. Epub 2012 Dec 14.
Soil microorganisms with potential for alleviation of abiotic stresses in combination with plant growth promotion would be extremely useful tools in sustainable agriculture. To this end, the present study was initiated where forty-five salt tolerant bacterial isolates with ability to grow in high salt medium were obtained from the rhizosphere of Triticum aestivum and Imperata cylindrica. These bacteria were tested for plant-growth-promoting rhizobacteria traits in vitro such as phosphate solubilization, siderophore, ACC deaminase and IAA production. Of the forty-five isolates, W10 from wheat rhizosphere and IP8 from blady grass rhizosphere, which tested positive in all the tests were identified by morpholological, biochemical and 16SrDNA sequencing as Bacillus safensis and Ochrobactrum pseudogregnonense respectively and selected for in vivo studies. Both the bacteria could promote growth in six varieties of wheat tested in terms of increase in root and shoot biomass, height of plants, yield, as well as increase in chlorophyll content. Besides, the wheat plants could withstand water stress more efficiently in presence of the bacteria as indicated by delay in appearance of wilting symptoms increases in relative water content of treated water stressed plants in comparison to untreated stressed ones, and elevated antioxidant responses. Enhanced antioxidant responses were evident as elevated activities of enzymes such as catalase, peroxidase, ascorbate peroxidase, superoxide dismutase and glutathione reductase as well as increased accumulation of antioxidants such as carotenoids and ascorbate. Results clearly indicate that the ability of wheat plants to withstand water stress is enhanced by application of these bacteria which also function as plant growth promoting rhizobacteria.
具有缓解非生物胁迫和促进植物生长能力的土壤微生物将是可持续农业中极其有用的工具。为此，本研究从冬小麦和白茅根际中获得了 45 株具有在高盐培养基中生长能力的耐盐细菌分离株，这些细菌在体外进行了植物促生根际细菌特性的测试，如溶磷、铁载体、ACC 脱氨酶和 IAA 生产。在 45 株分离株中，来自小麦根际的 W10 和来自白茅草根际的 IP8 在所有测试中均呈阳性，通过形态学、生物化学和 16S rDNA 测序鉴定为芽孢杆菌和恶臭假单胞菌，并被选为体内研究。这两种细菌都能促进六种小麦品种的生长，表现为根和茎生物量、植物高度、产量的增加，以及叶绿素含量的增加。此外，在细菌存在的情况下，小麦植物能够更有效地承受水分胁迫，表现在萎蔫症状出现延迟、处理过的水分胁迫植物的相对水含量增加、抗氧化反应增强。过氧化氢酶、过氧化物酶、抗坏血酸过氧化物酶、超氧化物歧化酶和谷胱甘肽还原酶等酶的活性升高以及类胡萝卜素和抗坏血酸等抗氧化剂的积累增加，表明抗氧化反应增强。研究结果清楚地表明，这些细菌的应用增强了小麦植物承受水分胁迫的能力，同时也作为植物促生根际细菌发挥作用。
