Improving Drought Tolerance by Exogenous Application of Ascorbic Acid in pepper seedlings

Drought is one of the major harmful abiotic factors that clearly affects the growth and development of plants. One of the most important non-enzymatic antioxidants in plants is ascorbic acid (AsA) that reduces the effects of drought stress. However the purpose of present study was to investigate the affect of different levels of drought and external application of AsA on physiological and morphological parameters in pepper seedlings. This experiment is based on a factorial arrangement in a completely randomized design setting up of two factors: drought (irrigation within the field capacity, moderate stress (irrigation within the 60% field capacity) and severe stress (irrigation within the 30% field capacity) and AsA in three leves (0 sprayed with distilled water, 0.5, and 1 mM) to three replications. The results illustrated that drought stress reduced fresh and dry weight of roots and shoots, relative water content (RWC), index chlorophyll except EC in leaves pepper seedling. Increasing foliar application levels of AsA significantly all measured parameters except EC. Increasing tolerance to AsA caused by drought stress in pepper seedlings seems to be due to increasing antioxidant properties in seedlings.