Foliar-applied calcium induces drought stress tolerance in maize by manipulating osmolyte accumulation and antioxidative responses

Influence of drought stress and foliar applied calcium (ca2+) on growth,water status,osmolyte accumulation and antioxidative defense system were evaluated in two maize hybrids,i.e. drought-tolerant dekalb-6525 (dk-6525) and drought-sensitive yousafwala hybrid (yh). drought stress caused substantial reduction in shoot dry matter (dm) production through disturbance in relative water content (rwc),protein metabolism and accelerating malondialdehyde (mda) accumulation and disproportioning antioxidant system. however,the accumulation of total free amino acids (tfa),glycinebetaine (gb) and activities of superoxide dismutase (sod),catalase (cat),peroxidase (pod) and ascorbate peroxidase (apx) were significantly increased by drought treatment. foliar treatment of ca2+ led to increase dm (49%),rwc (18%),accumulation of tfa (15%) and gb (25%) as well as the activities of sod (37%),cat (24%) and apx (49%) along with a decrease in mda content (24%) in both hybrids under water-deficit conditions. cultivar dk-6525 maintained relatively higher growth rate,water status,and osmolyte content and antioxidant activities than yh,irrespective of calcium supply and watering regimes. the results of the study suggested that optimal supply of ca2+ is effective to make plants vigorous to thrive under moisture-deficit conditions. © 2017,pakistan botanical society. all rights reserved.