INFLUENCE OF TRIACONTANOL AND MIXTALOL DURING PLANT MOISTURE STRESS IN LYCOPERSICON-ESCULENTUM CULTIVARS

The present investigation reports the effectiveness of 2 plant regulat ors in minimizing the impact of moisture deficits on tomato cultivars. Detrimental effects of water deficit on leaf area and phosphatase act ivity were evident up to the 7th day of stress which further enhanced with increasing stress up to the 10th day. Water deficits significantl y reduced leaf area in all the cultivars and a maximum reduction of 71 % over unstressed plants was recorded. Stress induced increase in acid phosphatase activity was significantly more in susceptible cultivars as compared to tolerant cultivars. Regulator application, prior to moi sture stress differentially lowered leaf area inhibition in stressed p lants than that in untreated plants, however, regulator appeared more effective up to the 7th day of stress only. Acid phosphatase activity was less in regulator treated plants than in untreated. Leaf drying at room temperature (24-degrees-C) up to 9 h caused significant increase in acid phosphatase activity in untreated plants. Inspite of comparat ively more fresh weight loss during leaf drying in regulator-treated p lants, enzyme activity was maintained at lower levels than that in unt reated plants.