Stress Physiology Laboratory, Department of Botany, J.N.V. University, Jodhpur, Rajasthan-342011.
*Corresponding author's
1Present address: Dr. (Mrs.) Sheela Agarwal, 13 Near Kuchaman House, Panch Batti Colony Ratanada, Jodhpur, 3420 11.
The role of antioxidant systems in protection against water and UV-B stresses was studied in Cassia angustifolia Vahl. and Cassia auriculata Linn seedlings at 5 and 7 days after sowing (DAS). Water and UV-B stresses increased superoxide dismutase (SOD) activity compared to control plants except at 5 DAS under water stress in C. angustifolia, where the SOD activity decreased. Peroxidase (POX) and polyphenol oxidase (PPO) activities increased in seedlings under both stresses at the two stages. Catalase (CAT) activity increased under both stresses except in C. angustifolia under UV-B stress, where the activity decreased 5 DAS. C. angustifolia seedlings exhibited high H2O2 and low ascorbate (ASA), thiobarbituric acid reactive substances (TBARS) and proline contents in comparison to C. auriculata seedlings. It is apparent that not only superoxide dismutase but H2O2 scavenging systems as represented by catalase and peroxidase, is also equally important in preventing oxidative stress induced by water and UV-B stresses. The high activity of polyphenol oxidase might also participate in the enhanced tolerance to oxidative stress.
Antioxidants, C. angustifolia, C. auriculata, oxidative stress, UV-B stress, water stress
