Physiologicalanalysis of NaCl tolerance in cell lines of Jatropha curcus L. grown in NaCl stress media

Sub culturing of callus pieces of leaf lamina origin on MS medium fortified with 2.5 x 10⁻⁶ M NAA and 5 x 10⁻⁶ M each of BAP and KIN and a range of NaCl concentrations (0 to 190 mM) revealed that 105 mM NaCl reduced callus growth by nearly 50%, hence it was selected for further experimentation. The callus pieces were sub-cultured for six generations on salt free and salt amended medium to get different callus lines i.e. control, unadapted salt stressed (on salt free medium for 5 generations and 6^th generation on NaCl supplemented medium), adapted (on salt supplemented medium for six generations), adapted→C (on salt supplemented medium for five generations and then shifted to salt free medium) and adapted→C→S (adapted for four generations on salt medium and finally shifted back to salt medium). Membrane injury was significantly high in salt treated calli. Protein content in unadapted salt stressed callus lines increased significantly over the control and it decreased in all other callus lines. NaCl increased proline content substantially in the unadapted salt stressed and adapted callus lines over the control callus line; the accumulation being most pronounced in the unadapted ones. Ascorbic acid content declined significantly in all the salt stressed callus lines. All the salt treated callus lines exhibited a significant increase in Na⁺ content while converse was true for K⁺ and Cl⁻contents.