The influence of Bacillus subtilis 10-4 on the hormonal system and water regime balance of wheat plants under dehydration

The work was devoted to the study of the influence of endophytic plant growth-promoting bacteria (PGPB) Bacillus subtilis strain 10-4 on wheat plants Triticum aestivum L. subjected to dehydration, induced by 12% PEG. Presowing seed treatment with endophytes at the concentration of 105 CFU mL−1 had stimulating and protective effects on the wheat plants growth under normal and stress conditions, respectively, which was judged on biomass accumulation, linear dimensions and visual appearance of the seedlings. The positive action of PGPB may be determined by the effects on the wheat hormonal system, as indicated by the data on increasing in the seedlings of the auxins content under normal conditions and prevention of its reduction under stress. PGPB-pretreatment decreased the stress-induced levels of abscisic acid (ABA) accumulation and cytokinin (CK) content diminution in the seedlings. Moreover the protective effect of B. subtilis 10-4 can be determined by their stabilizing effects on the membrane cell structures and water regime balance of wheat plants under dehydration.