Plants were developed through in vitro organogenesis of a NaCl-selected callus line of an endangered ornamental, Adenium multiflorum Klotzsch. Stepwise selection by gradual increase of NaCl concentration (0-100 mM) in the MS medium was found to be more effective for survival and growth of callus than direct transfer to salinity. Callus was developed aseptically from leaf explants in MS medium supplemented with NAA and kinetin. Comparing control, the selected (100 mM NaCl, stepwise) callus line exhibited significant increase in activities of antioxidant enzymes. Stability of salt tolerance of the selected callus was checked by growing the calli in NaCl free medium for 3 successive months, followed by re-exposure to higher salinity stress (120 mM). Under elevated salt stress (200 mM NaCl), the regenerants (S1) obtained from selected calli showed significantly higher antioxidant enzyme activities over both positive control (control callus derived plants in NaCl free medium) and negative control (control callus derived plants in 200mM NaCl). This ensured low level of lipid peroxidation and consequent good growth of S1 plants under high NaCl stress. Based on growth performance and antioxidant capacity, the S1 plants could be selected as NaCl-tolerant line.
