Nitric oxide in physiological potential and biochemical mechanisms of pea seeds under water deficit

Abstract: Nitric oxide (NO) has been standing out as a seed germination process stimulator, mainly under stress conditions. This work aimed to evaluate the physiological and biochemical effects of NO on germination and vigor of pea seeds submitted to water deficit. Seeds of cv. Itapuã 600 were sown in moistened substrate with water (control), PEG 6000 solution (-0.15 MPa) and PEG 6000 solution with sodium nitroprusside (SNP) (-0.15 MPa + 50 μM), an NO donor. The germination, vigor (germination speed and seedling development), activity of antioxidant enzymes, reactive oxygen species, lipid peroxidation, and amylase activity were evaluated. Germination and vigor of pea seeds were reduced under water deficit, but the application of SNP was able to improve the physiological and biochemical performance of the seeds under this condition. Water deficit promotes an increase in oxidative stress, but the application of NO promotes greater activity of antioxidative apparatus enzymes and amylases, softening the damage caused by water deficit during seed germination and growth of pea seedlings.