Does antioxidant capacity of leaves play a role in growth response to selenium at different sulfur nutritional status?

Abstract

There are evidences of beneficial effects of selenium (Se) on plant growth. In this work, using alfalfa (Medicago sativa L.) and two varieties of Brassica oleracea L. (cabbage and kohlrabi), the effect of Se addition (10 and 20μM) on growth and concentration of sulfur and Se was investigated in hydroponic experiments. In order to study the involvement of Se-mediated changes in the antioxidant capacity of plants in growth promotion by Se, the activity of antioxidant enzymes including ascorbate peroxidase (APX), catalase (CAT), peroxidase (POD), superoxide dismutase (SOD) and glutathione reductase (GR) and the concentration of H2O2 and glutathione were determined. It was demonstrated that sulfur sufficient cabbage and kohlrabi plants concomitant with growth stimulation in response to Se addition expressed a progressive oxidative stress as judged by a lower activity of antioxidant enzymes and accumulation of oxidants. Results imply that the function of antioxidant system of plants could not explain either the growth stimulatory effect of Se in cabbage and kohlrabi or different response of alfalfa plants to Se supplementation.

Keywords

• antioxidant system
• brassica oleracea l.
• medicago sativa l.
• se supplementation