Seed germination and physiological responses of quinoa to selenium priming under drought stress

The early stages of quinoa germination are sensitive to drought stress. For this purpose, a study entitled the effect of selenium in different concentrations on germination characteristics and some antioxidant enzymes of quinoa under drought stress conditions with polyethylene glycol (PEG 6000) was investigated. The first experimental factor was seed priming with selenium (from two sources: sodium selenate and selenium nanoparticles: SeNPs approximate to 33.4 nm) at 0.5, 1.5, 3, 4.5, 6 mg center dot L-1 concentrations, besides, no priming treatment was used as control. The second factor was drought stress with PEG 6000 in concentrations 0, -0.4, -0.8, and -1.2 MPa. Drought stress with accumulation of reactive oxygen species (ROS) had a negative effect on most of the measured traits. In seeds that were primed with appropriate selenium concentrations, germination parameters and antioxidant enzyme activity as well as proline and protein content increased compared to the control treatment. Under conditions of severe stress (-1.2 MPa), the highest activity of catalase (CAT), superoxide dismutase (SOD), and ascorbate peroxidase (APX) enzymes was observed in prime with selenium nanoparticles at concentrations of 4.5, 6.0 and 4.5 mg center dot L-1, respectively. Concentrations higher than 3 mg center dot L-1 of selenium nanoparticles and concentrations of 3 mg center dot L-1 sodium selenate had the highest accumulation of photosynthetic pigments under control (stress-free) conditions. The present study shows that selenium priming can reduce the harmful effects of drought stress on quinoa by altering germination properties and biochemical properties.