Cadmium toxicity causes oxidative stress and induces response of the antioxidant system in cucumber seedlings

Abstract

In this study, the effects of cadmium (Cd) on lipid peroxidation, electrolyte leakage, protein oxidation, ascorbate peroxidase (APX; E.C. 1.11.1.11), catalase (CAT; E.C. 1.11.1.6) and superoxide dismutase (SOD; E.C. 1.15.1.1) activities, and ascorbic acid, non-protein thiol groups and total soluble protein contents in cucumber seedlings (Cucumis sativus L.) were investigated. Seedlings were grown in vitro in an agar-solidified substrate containing four Cd levels as CdCl2 (0, 100, 400, and 1000 µmol L-1) for 10 d. The lowest Cd level decreased the malondialdehyde concentration. Electrolyte leakage increased only at 1000 µmol Cd L-1, whereas protein oxidation and total soluble protein content were enhanced at 400 and 1000 µmol Cd L-1. Activity of APX was inhibited while the activities of CAT and SOD were increased at all Cd concentrations. Ascorbic acid was enhanced at 400 and 1000 µmol Cd L-1 whereas non-protein thiol groups were increased at all Cd supplies. The results evidence the importance of the enzymatic and non-enzymatic antioxidant system in response to cadmium toxicity in cucumber seedlings.

Nitric oxide induced alleviation of toxic effects of short term and long term Cd stress on growth, oxidative metabolism and Cd accumulation in Chickpea

“…A similar accumulation of peroxides has been reported in response to Cd after 24 h treatment in Medicago sativa (Ortega-Villasante et al, 2005). Cadmium induced lipid peroxidation has also been observed in many plant species including pea (Sandalio et al, 2001;Rodriguez-Serrano et al, 2006), Oryza sativa (Choudhary and Panda, 2004), sunflower (Laspina et al, 2005), rice (Hsu and Kao, 2004), Arabidopsis thaliana (Cho and Seo, 2004), wheat roots (Singh et al, 2008), Phaseolus vulgaris (Smeets et al, 2005), and cucumber seedlings (Goncalves et al, 2007).…”

“…Most of the Cd is retained in roots and nodules of Cd treated plants. A higher accumulation of Cd in roots as compared to shoot has been reported by many workers (Sandalio et al, 2001;Dixit et al, 2001;Goncalves et al, 2007;Abdel-Latif, 2008). …”

“…Alteration in the activity of antioxidative enzymes with Cd stress has been reported by a number of workers (Dixit et al, 2001;Olmos et al, 2003;Hsu and Kao, 2004;Laspina et al, 2005;Rodriguez-Serrano et al, 2006;Goncalves et al, 2007;Singh et al, 2008;Mishra et al, 2008).…”

Physiological changes in osmo and hydroprimed cucumber seeds germinated in biosaline water

“…Sugars have a role in osmotic adjustment, but also have indirect effects of protection as in stabilization of proteins (Bianchi et al, 1991). Priming, by imposing a moderate osmotic stress to seeds, induces the concentration of osmolites, such as sugars, to keep the cell´s osmotic potential compatible with maintenance of stability of cell proteins, minimizing the loss of enzymatic activity or membrane integrity which occurs when there is water or saline stress (Gonçalves et al, 2007). Catalase (CAT) prevents formation of reactive compounds, converting hydrogen peroxide into water and oxygen, which are non-reactive oxygen species (Nakada et al, 2011).The activity of CAT in the hypocotyl-root axis of 2 DAS seedlings was not affected by either methods of priming imposed on cucumber seeds (Table 7).…”

“…Studies have shown priming affects activity of oxidative enzymes in the germination of seeds of different species (Ashraf and Foolad, 2005). However, not all cultures respond satisfactorily when developing in saline conditions, thus antioxidant defense mechanisms may provide a strategy to increase salt tolerance (Gonçalves et al, 2007).…”