In vitro physio and biochemical characterization of salt tolerance in rice (Oryza sativa L.) genotypes

Abstract

Abstract Salt stress induces oxidative damage to the cell by synthesizing reactive oxygen species. Salt-tolerant plants are potentially equipped with some defense mechanisms, such as enzymatic and non-enzymatic anti-oxidant properties. We attempted to characterize the physiochemical properties of the callus to select promising lines of rice at the cellular level under artificial salt stress induced by NaCl in vitro. In this study, we report the highest (19%) embryogenic callus induction frequency in CO 46 at higher NaCl stress (150 mM NaCl). Concerning the relative growth rate of the callus, we observed the highest RGE in BPT5204 and TRY1 suggesting that these could maintain a higher water potential and a fresh mass of the callus to survive salt stress. The genotype TRY 1 had the highest regeneration frequency (35%) in control (0 mM NaCl), but a significant reduction in RF (66%) was observed at 150 mM salt stress. The genotypes CO 50, CR 1009, and BPT-5204 registered the lowest regeneration frequency (6.7%) and produced a moderate number of shoots. Concerning the proline content high proline content in both the tolerant (BPT-5204) and sensitive (CO-46) cultivars was observed. Our result provided unique insight into the anti-oxidant properties of callus culture in rice. The anti-oxidative enzyme activities had increased progressively with increasing NaCl concentration in the medium. Genotypes BPT-5204 and TRY1 had a significant level of enzyme activities even at the highest NaCl treatments. Among the six genotypes, BPT-5204 and TRY1 were better in their performance with respect to the above parameters, which showed the physiological and biochemical homeostasis of the genotypes to salt stress.