DROUGHT STRESS IMPARED PHYSIOLOGY OF SUNFLOWER (Helianthus annuus L.) HYBRIDS REPARED BY PLANT GROWTH REGULATORS

Abstract

The present study was under taken to examine the modic effects of salicylic acid and ascorbic acid on mineral elements and leaf proline contents of two drought stressed sunflower hybrids (Hysun-33 and Hysun-38). Drought stress was imposed at vegetative and reproductive growth stages. Two concentrations of salicylic acid and ascorbic acid (100 and 200 mg L-1) were applied as a foliar spray at vegetative and reproductive stages and root treatment. Results revealed that imposition of drought stress at both the growth stages of both hybrids caused significant reduction for shoot nitrogen, potassium and calcium contents, whereas non significant reduction for phosphorous contents was noted. However, in contrast significant increase was noted for proline contents. However, exogenous application of all the (0, 100 mgL-1 and 200 mgL-1) concentrations of salicylic acid and ascorbic acid applied by either mode had a significant drought stress alleviative effects and increased the values of all the attributes, whereas, non significant increase was noted for phosphorus contents. Effect of foliar spray application was significantly higher for calcium and leaf proline than root treatment. Salicylic acid proved more effective than ascorbic acid, particularly, when applied at vegetative stage. Most effective concentration was 200 mg L-1 and maximum increase was recorded in Hysun-33