Comparative study of alleviating effects of GSH, Se and Zn under combined contamination of cadmium and chromium in rice (Oryza sativa)

Abstract

A hydroponic experiment was conducted to study the ameliorative effects of separate or combined application of exogenous glutathione (GSH), selenium (Se) and zinc (Zn) upon 20 μM cadmium (Cd) plus 20 μM chromium (Cr) heavy metal stress (HM) in rice seedlings. The results showed that HM caused a marked reduction in seedling height, chlorophyll content (SPAD) and biomass, and activities of catalase (CAT) and ascorbate peroxidase (APX) in leaves and H(+)-ATPase in roots/leaves, but elevated superoxide dismutase (SOD) and guaiacol peroxidase (POD) activities in leaves with elevated malondialdehyde (MDA) accumulation both in leaves and roots over the control. The best mitigation effect was recorded in HM+GSH+Zn and HM+GSH (addition of GSH+Zn and GSH to HM solution), which greatly alleviated HM-induced growth inhibition and oxidative stress. Compared with HM alone, HM+GSH and HM+GSH+Zn markedly reduced Cr uptake and translocation but not affected Cd concentration; improved H(+)-ATPase activity and Fe, Zn, Mn uptake and translocation, and repressed MDA accumulation. Meanwhile exogenous GSH and GSH+Zn counteracted HM-induced response of antioxidant enzymes, via suppressing HM-induced dramatic increase of root/leaf SOD and leaf POD activities, and elevating stress-depressed leaf APX and leaf/root CAT activities.

Accumulation of low-molecular-weight organic acids in roots and leaf segments of Zea mays plants treated with cadmium and copper

“…In some experiments, the induction of MDA, an oxidative marker, is more pronounced in roots than in leaves after metal stress, for example in Cu-stressed rice seedlings (Mostofa and Fujita 2013). In the case of Cd stress, the increase in the MDA content was similar in leaves and roots (Cao et al 2013). In our study, the level of stress monitored by the MDA level was more pronounced in senescent Zea mays leaves and more visible in the leaves after Cd treatment and in the roots after Cu application.…”

Influence of sulfate supply on selenium uptake dynamics and expression of sulfate/selenate transporters in selenium hyperaccumulator and nonhyperaccumulator Brassicaceae

“…Once absorbed, selenate can be loaded into the xylem, predominantly by the low‐affinity sulfate transporter SULTR2;1, and transferred to the aerial parts of the plant, where it can enter the sulfur reductive assimilation pathway to be converted into seleno‐amino acids. Additional sulfate transporters may be involved in the movement of selenate over plastid (SULTR3;1) and vacuolar (SULTR4;1 and SULTR4;2) membranes, or may assist in translocation (SULTR2;2, SULTR3;5) (Kataoka et al ., ; Cao et al ., )…”

“…Once absorbed, selenate can be loaded into the xylem, predominantly by the low-affinity sulfate transporter SULTR2;1, and transferred to the aerial parts of the plant, where it can enter the sulfur reductive assimilation pathway to be converted into seleno-amino acids. Additional sulfate transporters may be involved in the movement of selenate over plastid (SULTR3;1) and vacuolar (SULTR4;1 and SULTR4;2) membranes, or may assist in translocation (SULTR2;2, SULTR3;5) (Kataoka et al, 2004;Cao et al, 2013) Depending on environmental conditions (Se and S, in particular), a single plant will express different sulfate transporters, which may differ in selectivity for sulfate vs selenate (White et al, 2004). The inducible sulfate transport system in Arabidopsis thaliana, which is upregulated by low external sulfate concentration, has been reported to be more selective for sulfate over selenate than the constitutively expressed sulfate uptake system (White et al, 2004).…”

Indications of Selenium Protection against Cadmium and Lead Toxicity in Oilseed Rape (Brassica napus L.)

“…Among them, the application of chemical regulators to alleviate heavy metal toxicity and reduce plant heavy metal uptake in farmland contaminated with heavy metals, might be a practical and cost-effective strategy for sustainable utilization of natural resources and production of safe, high-quality agro-products. (Lin et al, 2012; Noriega et al, 2012; Cao et al, 2013; Ali et al, 2015). …”