Mercury induced phytotoxicity and oxidative stress in wheat (Triticum aestivum L.) plants

Abstract

The phytotoxicity and oxidative damage in response to different concentrations of Hg (0.0, 2.5, 5.0, 10 and 25 μM) were evaluated in wheat plants. The root and shoot growth, content of chlorophyll and total soluble protein declined at 10 and 25 μM Hg. Roots of the plant were more affected as compared to the shoot. The malondialdehyde (MDA) quantity enhanced in the roots of wheat plants treated with 10 and 25 μM Hg and in the leaves of plants treated with 25 μM Hg. The concentration of H 2 O 2 decreased at low concentration and increased at high concentration of Hg. The induction of enzymatic antioxidants (catalase, CAT; ascorbate peroxidase, APX; peroxidase, POX and superoxide dismutase, SOD) was found in the roots and leaves of plants with increased concentration of Hg up to 10 μM and low activities of these enzymes were observed at 25 μM Hg. Also, the level of K, Ca and Mg declined in leaf tissues of Hg treated plants. Thus wheat plants exposed to lower concentrations of Hg did not experience any oxidative stress. However, on treatment with 10 μM Hg, the roots and leaves responded differently. Both the leaves and roots of plants treated with higher concentration of Hg were subjected to comparatively greater oxidative damage and demonstrated that the antioxidative components were not able to remove the stress due to higher concentration of Hg and thus might affect the productivity in wheat plants.

Nutritional disorder in Pfaffia glomerata by mercury excess in nutrient solution

“…SAHU et al (2012) observed that the supply of Hg both at moderate (5µM) and high concentration (25µM) reduced the concentrations of K, Ca and Mg in Triticum aestivum. Reductions of K, Ca and other mineral nutrients under the influence of Hg have been reported in Marrubium vulgare and Rumex induratus (MORENO-JIMENZ et al, 2007).…”

“…In our previous studies (CALGAROTO et al, 2010;CALGAROTO et al, 2011), it was found severe lipid peroxidation of P. glomerata plantlets exposed at the highest level of Hg (50µM) tested. Increase in oxidative stress by reactive oxygen species in response to Hg has been observed in roots and leaves of Medicago sativa (ZHOU et al, 2008), Triticum aestivum (SAHU et al, 2012), Cucumis sativus (CARGNELUTTI et al, 2006), and several other plants. Active oxygen species bring about the peroxidation of membrane lipids (CARGNELUTTI et al, 2006;ZHOU et al, 2008;CALGAROTO et al, 2010), which leads to increased membrane permeability (SAHU et al, 2012).…”

“…Increase in oxidative stress by reactive oxygen species in response to Hg has been observed in roots and leaves of Medicago sativa (ZHOU et al, 2008), Triticum aestivum (SAHU et al, 2012), Cucumis sativus (CARGNELUTTI et al, 2006), and several other plants. Active oxygen species bring about the peroxidation of membrane lipids (CARGNELUTTI et al, 2006;ZHOU et al, 2008;CALGAROTO et al, 2010), which leads to increased membrane permeability (SAHU et al, 2012). In addition, it has been reported that Hg can replace some essential nutritients, such as Mg, Zn and Mn, causing a reduction in chlorophyll production and inhibiting the photosynthetic electron transport chain (RUIZ et al, 2003;PATRA et al, 2004;ISRAR et al, 2006).…”

“…Active oxygen species bring about the peroxidation of membrane lipids (CARGNELUTTI et al, 2006;ZHOU et al, 2008;CALGAROTO et al, 2010), which leads to increased membrane permeability (SAHU et al, 2012). In addition, it has been reported that Hg can replace some essential nutritients, such as Mg, Zn and Mn, causing a reduction in chlorophyll production and inhibiting the photosynthetic electron transport chain (RUIZ et al, 2003;PATRA et al, 2004;ISRAR et al, 2006).…”

“…It has been reported that in plants, Hg can replace some nutrients, such as Mg, Zn, and Mn, causing a reduction in chlorophyll production and inhibiting the photosynthetic electron transport chain (RUIZ et al, 2003;PATRA et al, 2004). MORENO-JIMENEZ et al (2007) reported that Hg increased the concentration of Fe by more than 40% in roots of Marrubium vulgare, but the translocation of Fe was reduced.…”