Role of Ascorbic Acid in Drought Stress Tolerance of Wheat Plant Triticum aestivum L.

Drought is a major abiotic stress, severely affecting the physiological processes and growth of plants. The present investigation aimed to evaluate impacts drought stress with three periods for irrigation: every 3 days(control), 6 days, 12 days foliar spray different concentrations ascorbic acid (0, 75, 150, 225) mg.L-1 on wheat plant. Pots experiment was conducted as completely randomized design replications in green house, Department Biology, College Education Pure Science (Ibn Al- Haitham), University Baghdad, during growing season, 2018 – 2019. results indicated that decreased plant hastened senescence flag leaves, which significantly associated decrease quality quantity grain yield. Foliar enhanced tolerance terms height, shoot dry weight, leaf traits (flag area, chlorophyll concentration macronutrients such nitrogen, phosphorous, potassium) some yield components (spike length, weight. pot-1 protein percentage grains). efficiency vegetative growth, plants affected by superiority 150 can resist unfavorable periods(12 days).