Abstract
Calcium (Ca2+) supplementation activate many downstream responses in plants to regulate their development and growth under saline conditions. In vitro experiments were conducted for investigating the ameliorating effects of calcium under saline conditions in date palm (Phoenix dactylifera L) cultivar, Khalas. The plantlets were subjected to NaCl stress (0, 100 and 200mM) in combination with CaCl2 (0, 5 and 10mM). Ionic concentrations of essential ions and growth characteristics were investigated. The number of leaves were improved with the CaCl2 supplementation significantly. Similarly, the 10mM Ca2+ significantly enhanced the leaf dry weight. With increasing NaCl levels, the dry weight was affected significantly with the decreasing ionic ratios. However, the supplementation of CaCl2 considerably improved these ionic ratios. With an increase in salinity, Na+, K+, Ca2+ and Mgt' increased significantly, while K+/Na+ ratio were decreased with increasing salt levels. However, the CaCl2 supplementation significantly improved K+/Na+ ratios. The transcript expression of NHX1 and HA1 genes was also investigated. The expression of NHX1 and HA1 was increased with increasing NaCl however, the addition of CaCl2 remarkably reduced the expression of both genes. The expression of NHX1 was more prominent in roots than shoots.