Decrease of the herbicide fenoxaprop phytotoxicity in drought conditions: the role of the antioxidant enzymatic system

This study investigated the effects of the herbicide from the graminicide group fenoxaprop, on oat plants under a normal and reduced water supply. The study was done in vegetative experimental conditions. It was established, that plants treated with fenoxaprop after 2 days following a reduction of the water content in soil with 60% to 40% of full field moisture capacity, significantly reduced phytotoxic action. At the decreased level of water supply in the oat plants, activity of antioxidant enzymes – superoxide dismutase, and catalase increased. The fenoxaprop action did not lead to a substantial increase in superoxide anion radical and hydrogen peroxide content, which had been observed under the action of the herbicide when normal levels of water were supplied to the plants. It was concluded, that the phytotoxic action of the herbicides from the graminicide group mediated the formation of reactive oxygen species and reduction of phytotoxicity on the background effect on plants of various stressors. This reaction was due to the increased activity of antioxidant enzymes, associated with nonspecific reaction of plants to these stressors