Germination performance and biochemical changes under drought stress of primed rice seeds

Abstract

Seed priming may improve germination performance of rice under drought. The present study was conducted to investigate the dynamics of seed biochemical changes during priming and post-priming germination under drought and to correlate those biochemical properties with the germination performance of primed seeds. The priming treatments were non-priming as control, hydro-priming and osmo-priming at -0.3, -1.0 and -2.2 MPa. All seeds were germinated under different levels of drought stress: 0 MPa as control, -0.2, -0.4, -0.6 and -0.8 MPa. The germination performance of hydro- and osmo-primed seeds at -0.3 and -1.0 MPa under severe stress (-0.8 MPa) was better compared with control and osmo-primed seeds at -2.2 MPa. Hydro-priming and osmopriming at -0.3 MPa significantly improved germination performance while germinated seeds of -1.0 MPa osmoprimed seeds recorded the highest root and total seedling length. Proline accumulation was significantly higher in seeds that were hydro-primed or osmo-primed at -0.3 or -1.0 MPa as compared with non-primed control seeds and seeds osmo-primed at -2.2 MPa. In addition, proline was significantly correlated with the starch and glucose content and α-amylase activity. Higher α-amylase activity would accelerate the process of starch hydrolysis into soluble sugar for embryo growth and development resulting in enhanced germination processes.