Comparative Evaluation of Spinach Biofortification with Selenium Nanoparticles and Ionic Forms of the Element

Abstract

The different forms of selenium nanoparticles include the least studied ones, both as a biofortification tool and in regards to the question of the mechanism of their accumulation. The effect of selenium nanoparticles and ionic forms of selenium on the growth and biochemical characteristics of male and female spinach plants are investigated. General properties typical both for nanoparticles and ionic forms of the element include a more intensive accumulation of selenium by male spinach forms, an increase in nitrate content in male plants and a decrease in female individuals, and the predominant accumulation of polyphenols by male forms. The effect of significant differences of nanoparticles and ionic selenium forms was demonstrated on the higher growth-promoting effect of nanoparticles when compared to selenate and selenite. The selenium fortification level decreased in the following way: selenate > nanoparticles of selenium > selenite. Differences between male and female accumulations of selenium are the largest for selenium nanoparticles and the lowest for selenate application. The increase in accumulation of ascorbic acid due to selenium biofortification is the least expressed for selenium nanoparticles. Contrary to ionic forms of selenium, nanoparticles maximally decrease the level of cadmium in female individuals. The results suggest the possibility of the participation of phytohormones (cytokinins and gibberellins) in the accumulation of selenium nanoparticles/ ionic forms and changes in biochemical characteristics of spinach plants as a result of biofortification.