Abstract
In this study, we investigated the role of seed priming in mitigating depressive effects of high salinity on membrane lipid composition and membrane functionality in seedlings of Hasawi rice cultivar (Oryza sativa L). Results indicated that seed pre-treatment with hydropriming (HP) and priming with 50 mM NaCl solution enhanced germination performance and early seedling growth under salinity condition. Priming treatments were found effective in maintaining membrane stability and integrity by increasing total membrane lipid content and reducing membrane damage. Concentrations of monogalactosyldiacylglycerol, digalactosyldiacylglycerol and phosphatidylglycerol were greatly increased when seeds were primed. Priming also increased phosphatidylcholine PC (lipid forming lamellar structure) and maintained phosphatidylethanolamine PE (non-bilayer-forming lipid) levels resulting in enhanced PC/PE ratio under salinity condition. Membrane unsaturation level was also increased, suggesting an improvement in membrane fluidity under salinity conditions. HP and NaCl-priming with 50 mM also induced increased contents of total phenolics, total soluble sugar and proline as compared to unprimed seedlings subjected to salinity. It is concluded that HP and priming with 50 mM NaCl solution can offer perspectives to improve germination and early growth of Hasawi rice under high salinity. This could be achieved through down-regulation of oxidative stress, accumulation of osmoprotectant compounds and improving cell membrane fluidity and integrity.