Intersexual differences in plant growth, yield, mineral composition and antioxidants of spinach (Spinacia oleracea L.) as affected by selenium form

The aim of the present study was the assessment of intersexual differences in yield, plant growth, mineral element composition and antioxidants content of spinach leaves under selenium application. Comparisons were made of three selenium treatments as foliar applications: sodium selenate (Se+6), sodium selenite (Se+4), not treated control. Female plants showed both higher leaf expansion and yield than the male ones and they were best affected by sodium selenate application. The male plant leaves accumulated higher amounts of Se, Li, Al, As, Cr and V, while the female forms showed higher concentrations of P, B and I. Sodium selenate enhanced the intersexual differences in terms of higher accumulation of Mn, Co, Ni in male plant leaves and Ca and K in the female ones. Intersexual differences of sodium selenite treated plants resulted in the predominant accumulation of Na, Zn and Cd by male plants and Pb by female individuals. Selenite treatment resulted in leaf nitrate decrease in female plants and increase in male ones. Within male plants, sodium selenate fortification resulted in the highest leaf dry residue, whereas sodium selenite and control led to higher dry residue in females than in males. Male forms showed higher polyphenols concentration, whereas under sodium selenate higher ascorbic acid, chlorophyll and carotenes were recorded in female individuals than in male ones. The results of this research suggest that plant biomass, mineral elements, antioxidants and nitrates accumulation depend on plant sexual form as well as on their relationship with selenium.