In vitro rice shoot apices as simple model to study the effect of NaCl and the potential of exogenous proline and glutathione in mitigating salinity stress

Abstract

This study was conducted using in vitro rice shoot apices cultures of two Malaysian rice cultivars—MR 220 and MR 253 to investigate the effect of NaCl and the exogenous application of proline and glutathione in mitigating the salt-induced damages. The results showed that high NaCl concentrations (150, 200, 250 and 300) mM significantly impeded plant growth resulted in reduction in plant height, root length, biomass and chlorophyll content. Results showed that the supplementation of proline and glutathione effectively ameliorates salt stress induced damages. The plant height recorded at 150 mM NaCl (control) were 9.8 and 10.3 cm for MR 220 and MR 253. With the supplementation of 5 mM proline, the plant height of MR 220 and MR 253 increased to 14.8 and 15.0 cm respectively. Similarly, the plant height of MR 220 and MR 253 was further increased to 20.3 and 21.3 cm when 10 mM glutathione was added exogenously. Fresh weight was recorded as 0.06 g in 150 mM NaCl media for both cultivars and increased to 0.13, 0.26, 0.16, 0.23 g (MR 220) and 0.11, 0.14, 0.27, 0.32 (MR 253) with the supplementation of 5, 10, 15 and 20 mM proline respectively. It was noted that supplementation of 5 mM proline successfully increase the endogenous proline content from 9.05 to 58.4 and 15.8 to 70.5 μmol/g for both MR 220 and MR 253 respectively. In addition, supplementation of 5 and 10 mM glutathione increased chlorophyll content from 7.0 mg/g (NaCl) for both cultivars to 13.09, 17.06 mg/g for MR 220 and 14.7, 12.6 mg/g for MR 253 respectively. These results highlighted the potential role of exogenously applied proline and glutathione in mitigating the detrimental effect of salt stress.