Studies On Improving The Capacity Of Salt-tolerance Of Cucumber By Bacillus Subtilis

Soil salinization and alkalization is a cosmopolitan problem effecting entironment and sustainable development of agriculture. At present salt stress is one of the adversities for restricting yield of group. Now under the situation of the area of infield is in decreasing continued and the fresh water is in shortage as the population is increasing more and more, how to make use of wide salina, wilderness and abundant salt water for developing agriculture is a global important problem. This paper studies the effect and conditions of Bacillus subtilis on improving the salt tolerance of cucumber under salt stress, and discusses the physiological mechanisms of Bacillus subtilis on improving salt tolerance of cucumber. SO it creates a new approach for improving salt tolerance of cucumber, and establishes the foundations of using Bacillus subtilis to enhance salt tolerance of cucumber. The main results are as follows:The inoculation method of seed coating and watering of juvenile plants is better than others. Using that method, population of Bacillus subtilis on cucumber rhizosphere were 7.49×10⁷CFU/g fresh weight of root. Under different concentrations of salt stress, population of Bacillus subtilis on cucumber rhizosphere were not different indistinctively, but the population decreased as the concentrations of salt stress rising. The result showed that Bacillus subtilis could colonize well on cucumber rhizosphere.Under no salt stress condition, Bacillus subtilis had positive effects on plant growth. Under 25mmol·L^-1NaCl stress, compared to no Bacillus subtilis treatment, Bacillus subtilis promoted the increase of leaf area and plant height, enhanced the activities of SOD POD and CAT, decreased the content of MDA, improved yield and quality of cucumber on certain extent. While under 50mmol·L^-1NaCl stress, Bacillus subtilis had no significant effects on cucumber growth compared to no Bacillus subtilis treatment. So under 25mmol·L^-1NaCl stress, Bacillus subtilis improves salt tolerance of cucumber to a certain extent.Under salt stress condition, appending exogenous application kalium and Bacillus...