Effect of strain Rs-5 containing ACC deaminase on growth and salt-tolerance of cotton seedling under salt stress

In order to elucidate the effect of strain Rs-5 containing ACC deaminase on growth and salt-tolerance of cotton seedling under salt stress,the growth biomass of cotton and four physiological indices(MDA,proline,soluble sugar and soluble protein content) of the cotton seedling were studied by pot experiment under different salt concentrations,different Rs-5 bacteria suspension concentrations and in different treatment methods respectively.The results showed that cotton growth and its salt-tolerance under salt stress were promoted by strain Rs-5,and this effect was more obviously as salt stress increased.When salt concentration is above 0.4%,the influence of Rs-5 to both cotton growth and salt-tolerance reached a significant level(P0.05),and reached a very significant level(P0.01) at a salt concentration 0.8%.Compared with control,the average plant height,root length,dry weight of cotton seedlings increased by 8.9%,10.1% and 17.5%,and proline,soluble sugar and soluble protein content increased by 17.9%,0.8% and 151.4% respectively,while MDA content decreased by 42.8%,and the stress relief and growth promotion of Rs-5 efficacy is the best,when the bacteria suspension concentration reached OD=0.3(about 108 U/ml).