Role of Ca2+ on Growth of Brassica campestris L. and B. juncea (L.) Czern & Coss under Na+ Stress

Root and shoot growth of Brassica campestris L. and B. juncea increased significantly (P < 0.01) with enhanced Ca2+ treatment along with 60 mM NaCl in the root medium. The maximum fresh mass of shoot and root in B. juncea was recorded at 10 mM Ca2+ concentration. The relative growth rate of shoot of both species reached its maximum at 8 mM of Ca2+ concentration. Average rate of Ca2+ intake (<(I)over cap>(Ca)) was higher in B. juncea than B. campestris. In B. juncea, the average transport of Ca2+ to shoot increased by 19%, 38%, 119%, 125% and 169% compared with the control. Furthermore specific utilization rate of Ca2+ was higher in B. juncea than B. campestris. In B. campestris it increased by 9%, 32%, 41% and 59% at 4, 6, 8, and 10 mM of calcium in comparison to 2 mM Ca2+ treatment. At 4, 6, 8 and 10 mM of Ca2+ application, the increase in the leaf area ratio was 10, 17, 23 and 30%, respectively. In the shoot and root portions of B. campestris and B. juncea, Ca2+ had a linear relationship with potassium and sulfur, whereas it was in antagonism with sodium ion.