RESUMO
A field experiment was conducted to study the impact of solar UV-B (280-315 nm) and UV-A (315-400 nm) components on the growth and antioxidant enzyme activity in cotton plant (Gossypium hirsutum var. Vikram). Solar UV components were excluded by filtering the sunlight through selective UV-B (<315 nm) and UV-B/A (<400 nm) absorbing polyester films. Plants grown under filters that transmitted solar UV served as controls. Exclusion of UV-B and UV-B/A enhanced plant height, leaf area and total biomass of plants. The activity of antioxidant enzymes superoxide dismutase (SOD), ascorbic acid peroxidase (APX), glutathione reductase (GR) and guaiacol peroxidase (GPx) assayed in the leaves were lesser in the UV excluded plants. The level of ascorbic acid and UV absorbing substances were also decreased by the exclusion of UV. Solar UV components exerted a limitation on the potential growth of cotton plants. Reduction in the antioxidant enzyme activity and ascorbic acid after UV exclusion indicated that ambient UV components exert a significant stress on cotton plants. Reduction in the production of UAS indicated a changed pattern of metabolism leading to improved primary metabolism. Exclusion of UV components is advantageous from the agricultural point to enhance the growth of cotton plants.
