Modulation of exogenous selenium in cadmium‐induced changes in antioxidative metabolism, cadmium uptake, and photosynthetic performance in the 2 tobacco genotypes differing in cadmium tolerance

Abstract

Hydroponic experiments were conducted using cadmium (Cd)-sensitive (cv Guiyan 1) and Cd-tolerant (Yunyan 2) tobacco cultivars to evaluate cultivar differences in response to Cd toxicity in the presence of selenium (Se). The results showed that addition of 3 µM Se in 50 µM Cd solution markedly reduced Cd accumulation in plants, alleviated Cd-induced growth inhibition, and increased nitrogen and chlorophyll contents as well as photosynthetic performance (i.e., net photosynthetic rate, stomatal conductance, and transpiration rate). External Se dramatically depressed Cd-induced O2 (•-) , H2 O2 , and malondialdehyde accumulation, especially in the sensitive cultivar. Selenium significantly elevated Cd-depressed activities of superoxide dismutase, peroxidase, catalase, ascorbate peroxidase, glutathione-peroxidase, and glutathione reductase in the both cultivars after 7-d treatments. Meanwhile, Se counteracted Cd-induced alterations in certain nutrient elements; for example, it significantly increased Zn and Ca concentrations and reduced Mg concentration in both cultivars. Furthermore, Se significantly elevated Cd-depressed H(+) -K(+) -adenosine triphosphatase (ATPase), Na(+) -K(+) -ATPase, and Ca(2+) -Mg(2+) -ATPase activities. The beneficial effect of Se under Cd stress may be related mainly to the increased ATPase activity and reduced Cd uptake and reactive oxygen species accumulation, thus reducing the negative consequences of oxidative stress caused by Cd toxicity.

Selenium reduces cadmium accumulation and alleviates cadmium-induced quality degradation in tobacco

“…The effect of Cd on essential elements varied with elements, which is consistent with our previous studies (Liu et al 2015). Specifically, we found Cd stress increased Cd and reduced K, S and Mg contention in tobacco leaves (Figures 1 and 2, Data are mass ratios of corresponding substances.…”

“…Se is an essential element for animals including humans. Similar to our previous study (Liu et al 2015), Cd concentration in Cd + Se treatments was decreased compared with Cd alone treatments (Table 3), while biomass increased significantly (data not shown). As was reported by Schützendübel et al (2001), Se and Cd could compete for the specific binding sites in carrier proteins.…”

“…Guiyan1 and Yunyan2 identified as Cd-sensitive and tolerant (Liu et al 2015), respectively, were used in this study. Seeds were germinated in sterilized moist vermiculite in a growth room at 22-25°C.…”

“…Although Se seems unnecessary to higher plants, many researchers have reported that Se could increase the tolerance of plants to many biotic and abiotic stresses (Feng et al 2013). Our previous study demonstrated that Se is able to decrease Cd uptake in rice and tobacco seedlings (Lin et al 2012, Liu et al 2015. However, little information is available about the effects of Se on the quality of tobacco grown in Cd contaminated soil.…”

Cadmium-induced Perturbations in Growth, Oxidative Defense System, Catalase Gene Expression and Fruit Quality in Tomato

“…Plants have adapted to mitigate the oxidative stress through antioxidative (enzymatic and non-enzymatic) mechanisms. The catalase (CAT), peroxidase (POD), and superoxide dismutase (SOD) are antioxidant enzymes that formulate integral component of oxidative defense system (Liu et al, 2015). CAT is one of the antioxidants with a high turnover of about 0.006 billion molecules of hydrogen peroxide to molecular oxygen and water per 60 s (Lee and An, 2005).…”