Impact of ascorbic acid-rich phyto-extracts on growth, yield and physio-biochemistry of okra [Abelmoschus esculentus (L.) Moench.] subjected to drought stress

Abstract

To overcome the negative effects of drought stress by exogenous application of natural [lemon juice (LJ) and orange juice (OJ)] and synthetic ascorbic acid (AsA) as sources of potential antioxidants was assessed in okra (A. esculentus) under field conditions. The experiment comprised of two cultivars (Sabz Pari and Bhindi Sanwali) those were subjected to different irrigation regimes including control (12 irrigations) as well as water deficit regimes such as D1 (eight irrigations) and D2 (six irrigations). The plants were sprayed with synthetic AsA (150 mg L-1), 50 % LJ and 50 % OJ to both control and water stressed plants after 30 days of seed germination. Foliar applied AsA obtained from varied sources significantly increased the plant biomass, yield characteristics and leaf photosynthetic pigments, total soluble proteins, proline, AsA, total amino acids, total phenolics, total soluble sugars, and activities of POD, CAT and SOD enzymes in okra plants under varying irrigations. Although, in contrast different AsA sources minimized the accumulation of H2O2 and MDA contents in okra plants. In conclusions, LJ and OJ (both 50 %) proved to be more effective than the synthetic AsA (150 mg L-1) in enhancing yield production, plant biomass and different physio-biochemical traits of okra plants subjected to varying water stress levels. Thus, a better organic source of AsA both LJ and OJ may be suggested to overcome the negative influence of water deficiency in plants.