tailieunhanh - Induction of phytochelatin and responses of antioxidants under cadmium stress in safflower (Carthamus tinctorius) seedlings

The glutathione content in leaves significantly increased with increasing Cd concentrations, whereas in roots glutathione contents increased up to a concentration of 50 μM Cd and then decreased. | S. NAMDJOYAN, S. NAMDJOYAN, H. KERMANIAN Research Article Turk J Bot 36 (2012) 495-502 © TÜBİTAK doi: Induction of phytochelatin and responses of antioxidants under cadmium stress in safflower (Carthamus tinctorius) seedlings Shahram NAMDJOYAN1,*, Shahrokh NAMDJOYAN2, Hossein KERMANIAN3 1 Department of Biology, Shahre Qods Branch, Islamic Azad University, Shahre Qods, Tehran - IRAN 2 Ministry of Agriculture, Land Affairs Organisation, Tehran - IRAN 3 Department of Pulp and Paper, Energy and New Technology Faculty, Zirab Rachis, Shahid Beheshti University, Tehran - IRAN Received: ● Accepted: Abstract: We investigated the role of antioxidant compounds (., α-tocopherol, phytochelatins, glutathione, and other non-protein thiols) in the cadmium (Cd) tolerance of safflower (Carthamus tinctorius L. cv. Arak2811) seedlings exposed to different concentrations of Cd (0-100 μM) for a week. A concentration- and tissue- dependent response to Cd was observed. Increasing Cd supply markedly reduced the dry weight of roots. Plants accumulated a substantial amount of Cd, especially in the roots. Levels of α-tocopherol showed a significant increase with an increase in the concentration of Cd in leaves. Upon Cd exposure, α-tocopherol levels followed a similar pattern in the root tissue with no significant change as compared to the control. Cadmium exposure caused a significant increase in non-protein thiols and phytochelatin levels in roots, whereas non-protein thiols and phytochelatin levels were not affected in leaves. The glutathione content in leaves significantly increased with increasing Cd concentrations, whereas in roots glutathione contents increased up to a concentration of 50 μM Cd and then decreased. The results indicate that the non-protein thiol and phytochelatin biosynthesis induction in roots and enhanced level of α-tocopherol and glutathione in leaves may be involved in Cd tolerance and hyperaccumulation in .