TY  - EJOU
AU  - Younis, Muhammad 
AU  - Akram, Nudrat Aisha 
AU  - Latef, Arafat Abdel Hamed Abdel 
AU  - Ashraf, Muhammad 

TI  - Appraisal of Improvement in Physiological and Metabolic Processes by Exogenously Applied Natural and Synthetic Ascorbic Acid in Okra (<i>Abelmoschus esculentus</i> L.) Fruit Subjected to Water Deficit Stress
T2  - Phyton-International Journal of Experimental Botany

PY  - 2023
VL  - 92
IS  - 10
SN  - 1851-5657

AB  - To counteract the effects of drought stress, scientists have adopted several approaches including the use of different chemicals both inorganic and organic, which is contemplated as a highly efficient and cost-effective shot-gun
approach. Ascorbic acid (AsA) is a potential organic substance, which widely occurs in plants, and is considered
to be an effective antioxidant to counteract reactive oxygen species (ROS). Thus, a pot experiment was performed
to assess the relative mitigating impacts of synthetic AsA and naturally occurring AsA in the form of lemon juice
(LJ) and orange juice (OJ) on two cultivars of okra (<i>Abelmoschus esculentus</i> L.) namely Sabz Pari and Bhindi Sanwali under varying water deficit conditions. After 30 days of seed germination, okra seedlings were subjected to
different irrigation regimes, i.e., water deficit stress [(65% and 50% F.C.) and control conditions (100% F.C.)].
Different levels of AsA [control (no spray), 14 mg L<sup>−1</sup> LJ, 24 mg L<sup>−1</sup> OJ and 150 mg L<sup>−1</sup> AsA] obtained from
different sources were applied as a foliar spray to control and water-stressed plants. Drought stress prominently
reduced plant growth and yield attributes of the okra cultivars. Water-deficit conditions (65% and 50% F.C.) substantially decreased the fruit chlorophyll (<i>a</i>, <i>b</i>) pigments and the activity of superoxide dismutase (SOD) enzyme,
while an increase was observed in the contents of fruit’s hydrogen peroxide (H<sub>2</sub>O<sub>2</sub>), malondialdehyde (MDA),
total phenolics, total soluble sugars, AsA, and total soluble proteins. Drought stress also increased the activities
of antioxidant enzymes like peroxidase (POD) and catalase (CAT). However, plant growth and yield attributes,
fruit chlorophyll pigments, total phenolics, total soluble sugars, total free amino acids, total soluble proteins,
AsA, GB, H<sub>2</sub>O<sub>2</sub>, and the activities of antioxidant enzymes (POD and CAT) were increased by the AsA exogenous
treatment in both okra cultivars under water deficit and control conditions. Overall, LJ and OJ were more effective
than the synthetic AsA in upregulating the physiological and metabolic processes of okra plants. So, cost-effective
as well as multi-nutrient natural sources of AsA could be suggested for alleviating the harmful effects of water
deficit stress on plants.
KW  - Okra; ascorbic acid; lemon juice; orange juice; drought tolerance

DO  - 10.32604/phyton.2023.028801