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.