Effect of phosphorus stress on antioxidant enzyme activities in wheat seedlings (Triticum durum Desf.) under in vitro culture

The study investigates the role of root glutathione (GSH) content and glutathione S-transferase (GST) activity in the response of hard wheat (Triticum durum Desf. variety Carioca) induced by different doses of phosphorus KH2PO4 and their relation to growth inhibition. Four doses were evaluated: control (0), 85, 170, and 340 mg/l. The experiment was carried out under in vitro culture conditions, during seven days. Results showed that P addition had a significant effect on growth parameters, root water content, and the amount of GSH and GST activity, but no significant changes were observed in chlorophyll contents. Treatment of seeds with KH2PO4 increased the GST activity from hard wheat roots and decreased GSH content. The GSH level in control was 2-fold greater than phosphorus 340 mg/l treatment. The highest induction of root GST activity compared to control was observed in 170 mg/l treatment. Phosphorus levels closely correlated with GSH (r²= -0.996***) and GST (r²= 0.991***).