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Effects of free and encapsulated co-culture bacteria on cotton growth and soil bacterial communities
- Guo, Lina, Wu, Zhansheng, Rasool, Aamir, Li, Chun
- European journal of soil biology 2012 v.53 pp. 16-22
- Bacillus subtilis, Klebsiella oxytoca, antioxidants, biomass, catalase, coculture, cotton, crop yield, damping off, encapsulation, leaves, peroxidase, shoots, soil, soil bacteria, soil salinization, species diversity, superoxide dismutase
- Soil salinization and cotton damping-off disease are limiting the cotton yield in the world. To overcome them, encapsulated co-culture bacteria was successfully applied. The study was carried out to evaluate the effects of free and encapsulated co-culture bacteria Klebsiella oxytoca Rs-5 and BCL-8 (mixture of Bacillus subtilis SL-13, SL-14 and SL-44) on promoting cotton growth, alleviating soil salinization stress and suppressing the growth of Rizoctonia solani. Both free and encapsulated co-culture bacteria resulted in the increase of cotton biomass, and the decrease of incidences of cotton damping-off disease, the activity of catalase (CAT), peroxidase (POD) and superoxide dismutase (SOD) of cotton leaves. Furthermore, the disease incidences of cotton plants treated with encapsulated co-culture bacteria were 20.45% lower than free co-culture bacteria. The dry weight and individual shoot length of cotton plant inoculated with encapsulated co-culture bacteria significantly increased (p < 0.05) 85.71% and 82.26%, respectively, compared to cotton damping-off disease and salinization stressed plants without bacteria. The bacterial richness of species in case of encapsulated co-culture bacteria was more than free one. At the end of the experimental period the bacterial richness of species of encapsulated co-culture bacteria treatment was similar to the soil of unstressed cotton plant due to the effect of encapsulated co-culture bacteria. Meanwhile, the varying trends of soil bacterial communities were consistent with the results of antioxidant enzymes with the same treatments. The study demonstrated that application of encapsulated co-culture bacteria could efficiently protect the cotton plants from negative stresses and promote the cotton growth in a long time via artificially regulating the soil bacterial community, without negatively affecting the bacterial richness of species in soil.