Antioxidant enzyme and plant productivity changes in field-grown tomato under drought stress conditions using exogenous putrescine

The growth and development of tomato seedlings (Solanum lycopersicum L.) are drastically inhibited under water stress. Putrescine (PUT) is involved in water stress tolerance. However, very limited information is known concerning the effects of exogenous application of PUT on plants including tomato. This experiment was carried out to study the application of putrescine on some physiological and biochemical factors of tomato under the water stress. Plants were exposed to three water conditions: 100 % (ET0) as well- watered treatment (or control), 75 and 50% of ET0 as a water stress treatments. Foliar applications of PUT were applied at 0.5 and 1 mgL-1 while control plants were sprayed with distilled water. Drought stress significantly impaired the plant growth and productivity, and reduced leaf area, plant height, fruit yield at 50% ET0 compared to control treatment. Also antioxidant enzymes such as SOD, PPO, and CAT were increased by increasing the water stress conditions. The application of PUT improved the growth characters, plant height, fruit yield, and leaf area under water stress. Furthermore, PPO content and CAT and SOD enzyme activities were also improved by applying PUT. The results of this study indicated that foliar application of putrescine in proper level may act as elicitor to trigger physiological processes and induce valuable metabolites biosynthesis, which may compensate the negative impacts of drought stress on plant biomass, quality and quantity.