Journal of Plant Process and Function

Selenium (Se) is known as an essential nutrient for human health. More than 15% of world population suffers Se deficiency mainly due to consumption of poor Se food crops. Bio fortification has been introduced as a sustainable and cost-effective approach to combat Se deficiency in the food chain. In this study, the effect of selenite (SeO₄^2-), sulphate, and certain amino acids on yield and bulb selenium concentration with the aim of Bio fortification programs was investigated. Two onion cultivars (Allium cepa L., cvs. Dorrcheh and Cebolla Valenciana) were grown in nutrient solutions in which 20% of nitrate was replaced with arginine, histidine, or mixed amino acids extracted from blood powder and exposed to two levels of sulfate (1 and 3 mM) and two levels of selenate (0 and 25 uM). Application of different amino acid treatments in the presence of selenite and sulphate increased yield of onion bulb. This increase was greater in Valenciana compared with Dorrcheh. In both onion cultivars, the highest Se and sulfate concentration was observed at the mixed blood powder-extracted amino acid treatment. Selenium nutrition at the level of 1 mM sulfate and in the presence of amino acids mixture, created the highest concentration of Se in the Valenciana (55.8 µg g^-1). Increasing Se level had no effect on the sulphate concentration of both onion cultivars while increasing of sulphate concentration in the nutrient solution caused a reduction in Se uptake. Increasing sulfate concentration increased pyrovic acid concentration of both onion cultivars but addition of Se, reduced concentration of pyrovic acid in Valensiana exposed to 1 mM sulfate treatment by 15%.