Stem Cell 2013;4(2) http://www.sciencepub.net/stem 1 Using Silicon to Ameliorate the Deleterious Effects of Drought on Wheat (Triticum Aestivum L.) Ahmed S. M. Morsy 1 and Naheif E. M. Mohamed 2 1 Agronomy Dept. Fac. of Agric. Minia Univ., 2 Agronomy Dept. Fac. of Agric. Sohag Univ., Egypt. Abstract: Silicon is known to ameliorate the deleterious effects of drought on plant growth. This study was a trial for evaluating growth and nutritional status of wheat cv. Sids- 12 on different soil water deficits as influence by silicon application. Silicon in the form of potassium silicate was added to the soil at 150 and 200 mg/ kg -1 soil. Plants were grown under three levels of soil water contents namely 50 %, 75 % and 100 % of field capacity. Water stress conditions especially at 50 % field capacity was responsible for reducing growth aspects, spike weight, leaf water content %, plant pigments and concentrations and uptake of N, P, K, Mg, Ca and Si at all levels of water content. Drought treatments considerably enhanced H 2 O 2 in the leaves. Poor growth and nutritional status of wheat seedlings grown under water deficit conditions was measurably improved with silicon application. In water deficit area where wheat cv. Sids- 12 are planted, its is essential for using silicon. [Ahmed S. M. Morsy and Naheif E. M. Mohamed. Using Silicon to Ameliorate the Deleterious Effects of Drought on Wheat (Triticum Aestivum L.). Stem Cell 2013;4(2):1-8] (ISSN 1545-4570). http://www.sciencepub.net . 1 Keywords: Silicon; Ameliorate; Deleterious Effect; Drought; Wheat (Triticum Aestivum L.) 1. Introduction Drought stress usually causes a reduction in crop production. It inhibits the photosynthesis of plants, causes changes of chlorophyll contents and components and damaged of photosynthesis apparatus. It also, inhibits the photochemical activities and decreases the activities of enzymes in the calvin cycle (Baligar et al., 2001). One of the important reasons that environmental stress inhibits the growth and photosynthetic abilities of plants is the breakdown of the balance between the production of reactive oxygen species and the antioxidant defense causing accumulation of oxygen species which induces oxidative stress to proteins, membrane lipids and other cellular components (Alvi and Sharif, 1995). The antioxidant defense system in the plant cell includes both enzymatic such as perioxidase and non- enzymatic constituents such as ascorbic acid. In case of drought, high activities of antioxidant enzymes and non- enzymatic constituents are important for plants to tolerate stresses (Iturbe- Omaetxe et al., 1998). Silicon (Si), the second most abundant element in the earth's crust, has not yet received the title of essential nutrient for higher plants, as its role in plant biology is poorly understood (Epstein, 1999). However, various studies have demonstrated that Si application increased plant growth significantly (Alvarez and Datnoff, 2001). Beneficial effects of Si are more prominent when plants were subjected to multiple stresses including biotic and abiotic stresses (Aziz et al., 2002; Rodrigues et al., 2003; Ma, 2004; Tahir et al., 2006). Silicon is also known to increase drought tolerance in plants by maintaining plant water balance, photosynthetic activity, erectness of leaves and structure of xylem vessels under high transpiration rates (Melo et al., 2003; Hattori et al., 2005). Gong et al., (2003a) observed a great promotion on water economy and dry matter yield of water by Si application. Silicon application is reported to enhance leaf water potential under water stress conditions (Matoh et al., 1991). They suggested that a silica-cuticle double layer formed on leaf epidermal tissue is responsible for this higher water potential. Lux et al. (2002) reported that endodermal tissue accumulates large amounts of Si in drought tolerant cereal cvs. Jones and Handreck (1999); Hattori et al. (2003); and Lux et al. (2003) suggested that Si plays an important role in water transport and root growth under drought conditions in sorghum. Previous studies show that application of silicon is useful for drought stress tolerance improvement of crops in relative to non- silicon treatment under drought (Alvi and Sharif, 1995; Rafi et al., 1997; Akram et al., 2004; Gong et al., 2005; Gunes et al., 2006; Mitani and Ma, 2005 and Rahmatullah et al., 2007). Samarah et al., (2004) confirmed the beneficial effect of using silicon in alleviating the adverse effects of drought on growth of Soybean. To ensure food security and sustainable economy, it is extremely important to find ways to improve drought tolerance of wheat. Keeping in view the importance of wheat, it is essential for testing the beneficial effects of silicon on wheat cv. Sids- 12 grown under different soil water contents. 2. Material and Methods This pot investigation was conducted in greenhouse located at Sohag district, Sohag