biologia plantarum

Biologia plantarum 51:546-550, 2007 | DOI: 10.1007/s10535-007-0118-5

Cadmium mitigates ultraviolet-B stress in Anabaena doliolum: Enzymatic and non-enzymatic antioxidants

P. Bhargava¹, N. Atri¹, A. K. Srivastava¹, L. C. Rai^1,*

¹ Laboratory of Algal Biology, Center of Advanced Study in Botany, Banaras Hindu University, Varanasi, India

Impact of ultraviolet-B (UV-B) and Cd, applied individually and in combination, measured in terms of oxygen-evolution, chlorophyll (Chl) and protein contents, lipid peroxidation, and enzymatic and non-enzymatic antioxidants of Anabaena doliolum, revealed a greater oxidative damage induced by UV-B than by Cd. While superoxide dismutase (SOD) showed a greater stimulation by UV-B than Cd, the activities of catalase (CAT) and glutathione reductase (GR) declined after UV-B treatment. Cd treatment, however, enhanced the activities of ascorbate peroxidase (APX) and GR. CAT activity increased at low but decreased at high dose of Cd. Increase in carotenoid (Car) content in UV-B treated cells suggested a shielding effect of Car against UV-B stress. A 15-and 10-fold rise in α-tocopherol (α-TOC) content at high dose of Cd and/or UV-B offered testimony to the antioxidant role of α-TOC.

Keywords: α-tocopherol; ascorbate; antioxidative defence system; carotenoids; chlorophyll; oxidative damage

Subjects: Anabaena doliolum; antioxidants, antioxidant enzymes; ascorbate peroxidase; cadmium; carotenoids; catalase; chlorophyll a,b; glutathione reductase; malondialdehyde; metals; plant defence system; reactive oxygen species (ROS); salinity, salt stress; UV radiation, stress

Received: October 5, 2005; Accepted: May 2, 2006; Published: September 1, 2007Show citation