DIFFERENTIAL ANTIOXIDANT RESPONSE ON DROUGHT BY ZONES OF THE GROWTH OF MAIZE LEAVES

The effect of drought on the antioxidant system of maize protection taking into account the geo-ecological factors of their growth was studied. The samples studied grew in the coastal areas of the Debet, Shnogh and Araks rivers of Republic of Armenia. Antioxidant activity was determined by four biochemical parameters, depending on the degree of optimum relative soil moisture (mild – 43% and severe – 34%). The selection of plant material was carried out during the growing season at the test sites in clear dry weather. Combining the kinematic analysis of maize leaf growth zones with biochemical measurements allowed investigating the correlation between the regulation of cellular processes of cell division and cell elongation and molecular redox regulation in response to drought. The biochemical analysis of the antioxidant activity system in both control samples and those subjected to moderate and severe drought allowed us to associate drought tolerance and stress tolerance with redox regulation by zones of maize leaf growth. It has been established that stress tolerant maize is less affected by the drought in the zone of meristem since here they are better protected in drought conditions. The content of malonic dialdehide in all areas of growth of corn samples was slightly lower under control conditions but increased in response to drought. In the control samples, a decrease of concentration of the ferric reducing ability of plasma in the direction from the zone of the meristem to the zone of mature is noticeable, keeping the same tendency during drought. By the concentration of polyphenols and flavonoids, a steady decrease is observed along the axis of growth of the leaf of maize and a gradual increase with the development of stress of water deficiency.