Biomics

Soil salinity inhibits growth of glycophyte plants, to whom cultivated plants belong, resulting in their decreased productivity. The area of salinized soil increases due to aridness of climate and watering, demanding the study of the mechanisms of growth inhibiting action of salinity and an increase in salt resistance. Application of growth promoting bacteria is a mean to increase plant resistance to salinity and the study of the mechanisms of their action attracts great attention. The goal of the present work was in testing suggestion that the increase in salt resistance brought about by growth promoting bacteria is due to plant protection from oxidative stress.

We performed bacterization of wheat seeds with phosphate mobilizing bacteria Advenella kashmirensis IB-K1, cytokinins producing Bacillus subtilis IB-22 and Pseudomonas extremaustralis IB-K13-1 characterized by high level of phosphate mobilization and auxins production. Seeds of wheat Omskaya 35 (Triticum aestivum L.) were places into Petri dishes on water or 100 mM NaCl. On the third day of experiment, seedlings were weighted and MDA, proline concentration was estimated.

On the background of 100 мМ NaCl, seed treatment with phosphate mobilizing bacteria did not influence the growth of wheat seedlings, whereas the treatment with hormone producing bacteria resulted in positive effect. Presence hormone producing bacteria protected plants from oxidative stress suggested by lower levels of MDA, but the best results were obtained with cytokinins producing bacteria. Maximal accumulation of proline was detected in the plants treated with A. kashmirensis IB-K1 that was 2.5 higher than in the variants with the seed treatment with B. subtilis IB-22 and 1.5 higher in the variant with P. extremaustralis IB‑K13‑1A treatment.

It is concluded that the effect of microbial hormones on the reduction of the level of reactive oxygen species and that the increase in growth rate during bacterization of wheat seeds by hormone-producing microorganisms is not associated with proline accumulation.

salinity, PGPR, phytohormones, oxidative stress, wheat

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