Morphological and physiological-biochemical response of plants to treatment with hydrocarbon bacteria on the background of oil contamination

In the field experiment, the effect of hydrocarbon-oxidizing auxin-producing bacteria Enterobacter sp. UOM 3 and Pseudomonas hunanensis IB C7 on some morphological and biochemical indicators of stress in barley plants was studied. Stress is caused by oil entering the soil. Throughout the experiment, the pollutant had an inhibitory effect on the length and weight of roots and shoots of barley plants, as well as on the size of leaves. Under such conditions, bacterialization by each of the strains caused an elongation of shoots, an increase in the wet weight of roots and shoots, and an increase in the leaf surface index compared to untreated plants in contaminated soil. In addition, the P. hunanensis IB C7 strain had a positive effect on root length. In the presence of oil, an increase in the ABA content in plants was found, to a greater extent in the roots than in the shoots. The use of bacteria reduced the amount of the hormone to values comparable to that in plants in clean soil. The level of chlorophyll in plants growing in the presence of oil was lower than in the control variant, but inoculation with microorganisms contributed to its increase. The minimum amount of flavonoids was found in control plants. In the presence of oil, the amount of flavonoids increased and was higher in the treated plants. Thus, it was found that bacterization reduces the negative consequences for barley plants caused by the ingress of oil into the soil. This was manifested in the improvement of some morphological characteristics of inoculated plants and was accompanied by a change in a number of their physiological and biochemical characteristics. Key words: oil pollution, barley plants, bacterization, Enterobacter sp., Pseudomonas hunanensis, abscisic acid, chlorophyll, flavonoids, nitrogen balance index.