Exogenous foliar application of abscisic acid on polyethylene glycol induced drought by improving the morphological and biochemical characters of four rice (Oryza sativa L.) varieties

Abstract

Climate change is one of the critical defining concerns today’s world, altering earth ecosystem. Drought stress management is a major issue in agricultural and crop research, mainly negatively impacting rice growth and yield. Abscisic acid (ABA) is a plant stress hormone that plays a crucial role in regulating, and mitigating drought stress. The objective of this study was to evaluate the effect of exogenously applied ABA and adaptation strategies responding to concrete challenges four rice varieties (ASD-16, ADT-45, TKM-13 and CO-50) and analysed growth characteristics, physiological, biochemical and antioxidative enzyme activities induced by polyethylene glycol (2 % and 4 %) drought stress and exogenously application of ABA (100 µM). The present findings help predict the degree of drought resistance variety of rice. The experiment was designed by six different treatments, such as control plants, control + ABA, polyethylene glycol induced drought (2 % and 4 %), and combination treatment of 2 % and 4 % PEG with exogenous application of ABA (100 µM). Exogenous ABA treatment significantly increased in morphological characteristics compared to control. The chlorophyll pigments, RWC, biochemical parameters such as reducing sugar, starch, protein and antioxidant activities of CAT, POD were increased and proline content was decreased at PEG 2 % and 100 µM ABA-treated rice in TKM-13 compared to ASD-16, ADT-45, CO-50. There were statistically significant morphological, physiological and biochemical parameters between treatments. The present findings depict that four rice varieties under drought imposition decrease the growth characteristics, physiological and biochemical content. However, the PEG induced drought (2 %) and foliar application of ABA (100 µM) were found to increase morphology, physiological and biochemical contents and can provide valuable insights into plants’ drought responses and may help identify novel drought tolerance traits.