The Role of Uniconazole in Improving Physiological and Biochemical Attributes of Bean (Phaseolus vulgaris L.) Subjected to Drought Stress

Adverse environmental conditions such as drought are among the major factors limiting the growth and productivity of land plants. Plant growth regulators are defined as naturally occurring or synthetic compounds that affect the development or metabolism of higher plants, mostly in abiotic stress conditions. Two varieties of common bean, Talash (Sensitive) and Dehghan (Tolerant) were used to examine the influences of uniconazole on the photosynthetic traits, antioxidant activities, and morphological parameters of bean leaves and root under drought stress conditions. Results showed that drought stress considerably depressed the plant growth. However, the drought-stressed plants treated with uniconazole showed significantly higher biomass than in plants without uniconazole. Uniconazole treatments on Dehghan showed superior results to those on Talash. The leaves of uniconazole plants exhibited an increased leaf greenness content, photosynthetic rate, transpiration rate, and stomatal conductance but lower lipid peroxidation content and relative electrical conductivity compared to those of drought-stressed plants. Soluble sugar, soluble protein content, and the activities of superoxide dismutase, peroxidase, and catalase in the leaves were increased by uniconazole in drought stress and under well-watered conditions. Finally, the findings indicated that uniconazole can effectively alleviate the adverse effects caused by drought stress; these unwanted changes are partially attributable to the modifications in morphology and physiological characteristics resulting in yield increase in drought bean. © 2019, Korean Society of Crop Science and Springer.