Effect of Foliar Application of Ascorbic Acid on Growth, Yield Components and Some Chemical Constituents of Wheat Under Water Stress Conditions

A greenhouse pot experiment was carried out during October 26, 2009 to May 15, 2010. Winter wheat grains (Triticum aestivum L.) cv.Rizgary was used to investigate the role of spraying the plant with 200ppm ascorbic acid (AsA) on vegetative, biomass and some chemical and biochemical constituents of leaves under drought condition. The water stress treatments were: irrigation every 3day- well watered control, 7, 14 and 21 days interval during 90 days. Under water deficit conditions, the vegetative growth and yield components of plant were decline, in addition marked changes in the level of mineral ions and biochemical constituents of leaves were observed. Plant height, shoot dry weight, flag leaf area, water content and leaf growth elongation rate decreased significantly by increasing drought stress, while root dry weight and root: shoot increased. Chemical constituents of leaves such nitrogen, phosphorus, potassium and magnesium were decreased, proline and AsA increased significantly with increasing drought stress and the highest values obtained at 21 day water regime. Soluble sugar, total carbohydrates, total protein, chlorophyll a, b and total carotenoid of leaves were also decreased and the highest reduction in parameters recorded at 21days water regime. Spikes length, number of spikes/plant, weight of spikes, 100 grain dry weight, grain numbers and grain yield were also decreased. However, AsA treatments alleviated the inhibitory effect of drought through enhancing above mentioned parameters.