Amelioration of drought stress in black matpe bean (Vigna mungo L.) by foliar application of potassium

Growth, physiological and biochemical activities of black matpe bean grown in pot cultures were evaluated to recognize the ameliorative role of potassium against the deleterious effects of water deficit. Black matpe plants were subjected to four levels of water stress (400 ml, 200 ml, 100 ml and 50 ml). The control plants were supplied with 500 ml of water at regular intervals. Potassium was applied in form of 200 ppm KCl and KNO3. Plants were under observation starting from 25 upto 55 days of plant growth at 10-day interval for each treatment. Water deficit stress reduced biomass, leaf area and RWC and provoked oxidative stress in plants as confirmed by considerable increase in electrolyte leakage, proline and reducing sugar content. Foliar application of KCl and KNO3 improved all these attributes under water stress. The ameliorative effect might be maintained through decrease in proline and increase in reducing sugar content. Increased reducing sugar content in K treated plants may have a significant role in osmotic adjustment.