Potassium nitrate and silicon dioxide priming improve germination, seedling growth and protective enzymes of rice var. FARO44 under drought

Priming of seed is an approach that imparts stress tolerance to germinating seeds and seedlings under stressful conditions. Drought stress is a key reason for crop failures. We evaluated the effects of seed priming with 2.5% & 5% & KNO3 and 3% & 3.5% SiO2 on germination, seedling growth, protective enzymes and biochemical attributes of 3-weeks old FARO44 rice seedlings under drought conditions induced by polyethylene glycol (PEG6000). Priming experiments were arranged in a completely randomized design with every treatment replicated five times. The results revealed that KNO3 and SiO2 priming significantly enhanced germination, seedling growth, catalase, and ascorbate peroxidase and superoxide dismutase activities of rice seedlings about 2 folds compared to unprimed seedlings under drought. Priming treatments also improved protein, total chlorophyll, carbohydrate, soluble sugar and proline contents & decreased malondialdehyde content and leaf electrolyte leakage of rice seedlings. Between the two treatments, KNO3 priming was found to be more effective on enhancing germination, protective enzymes' activities and biochemical attributes of rice seedlings. Thus, FARO44 rice priming with KNO3 is suggested for faster germination and growth of seedlings in dry ecosystems.