Effect of Different Levels of Nano-Selenium and Selenium on Seed Germination and Seedling Growth of Onion (Allium cepa L.)

Selenium (Se) is a metalloid element whose antioxidant properties have been confirmed for humans, animals and plants. Selenium is considered as an essential element in some organisms, but its high concentrations lead to toxicity in plants. Selenium is an essential nutrient, but its role in plants requires more research. So in this research, the effect of different concentrations of selenium (sodium selenate and sodium selenite) and selenium nano-particles (Nano-Se) on onion (Allium cepa L.) seed germination properties and seedling growth was studied. The experimental treatments included four concentrations of sodium selenate and sodium selenite and selenium Nano-Se (5, 10, 15 and 20 mg L-1) and control (distilled water). Different forms and concentrations of selenium had significant effect on onion seed germination. The highest germination percentage (100%) was observed in 10 mg L-1 Nano-Se treatment. Selenium had a positive effect on the length and fresh weight of onion root compared to the control treatment, the lowest amount of root length was observed in the control treatment. Low levels of selenium had a positive effect on the activity of superoxide dismutase, catalase and peroxidase enzymes. Adding Nano-Se in concentrations 10 and 15 mg L-1 could promote the seed germination of onion compared to sodium selenite and sodium selenate.