Calcium chloride enhances growth and physio-biochemical performance of barley (Hordeum vulgareL.) under drought-induced stress regimes: a future perspective of climate change in the region

Abstract Water is the fundamental part of living systems and it plays a key role in supporting life on earth; however, fluctuations in climatic conditions lead to limitation of the ground water causing serious concerns. The present research study was aimed at assessing growth and physio-biochemical responses of barley to calcium chloride (CaCl2) solution (10 mM) applied through roots under induced drought stress for 5, 10, and 15 days. CaCl2, being an enhancer of osmolytes and antioxidant enzymes, counteracts the damaging effects caused by abiotic stresses. A pot experiment was conducted by sowing barley under induced drought stress for 5, 10, and 15 days, respectively. Plants exposed to different levels of the induced drought stress condition were treated with 10 mM of CaCl2 solution via roots during the seedling stage. Results indicated that water-limited conditions negatively affected plant growth parameters including final emergence percentage, final germination percentage, and mean emergence time. Moreover, absolute growth rate, relative growth rate, and net assimilation rate were significantly improved under 5, 10, and 15 days of drought stress supplemented with CaCl2 solution. Under drought conditions, an increase was observed in hydrogen peroxide (H2O2), glycine betaine (GB), and proline (PRO) content, and in ascorbate peroxidase (APX), catalase (CAT), peroxidase (POD), superoxide dismutase (SOD), and lipid peroxide (LPO) activities. H2O2 and LPO showed a significant decline with CaCl2 application under induced drought stress regimes. On the contrary, GB, PRO, APX, CAT, POD, and SOD contents of root and leaf were significantly improved with CaCl2 application under induced drought stress. In conclusion, CaCl2 solution effectively curbed the damages caused by oxidative stress via accumulating osmolytes and scavenging reactive oxygen species by activating the antioxidant enzymatic defence system of barley.