RT Journal Article
T1 Differential alterations of antioxidant defenses as bioindicators of mercury and cadmium toxicity in alfalfa
A1 Sobrino Plata, Juan
A1 Ortega Villasante, Cristina
A1 Flores Cáceres, Laura
A1 Escobar, Carolina
A1 Del Campo, Francisca
A1 Hernández, Luis
AB Several physiological parameters related to oxidative stress, which is a characteristic of plants exposed to toxic metals, were studied in 3-week-old alfalfa plants treated with cadmium (Cd) or mercury (Hg) at doses of 0, 3, 10 and 30 μM for 7 d. The concentrations of biothiols, glutathione (GSH), homoglutathione (hGSH) and phytochelatins (PCs) increased dramatically in metals-treated plants, in particular in the presence of Cd. This was accompanied by a remarkable up-regulation of γ-glutamyl cysteine synthetase gene, probably in response to the higher demand for GSH|hGSH needed for PC synthesis. The presence of metals enhanced lipid peroxidation in shoots, while chlorophyll content declined in a concentration dependent manner. Ascorbate peroxidase (APX) activity increased moderately in roots of Cd-exposed plants, and a new basic root peroxidase isoform was found in both Cd- and Hg-treated plants. Glutathione reductase (GR) activity was enhanced in shoots of plants exposed to Cd and Hg. However, this enzymatic activity showed a metal dependent response in roots, and was enhanced in Cd-treated plants but was severely inhibited in roots of plants treated with Hg. Inhibition of GR by Hg was confirmed in vitro by incubating a commercially available GR and control shoot extracts with several doses of Hg and Cd. Ascorbate concentrations were elevated with treatments of 3 μM Hg, 10 μM Cd and 30 μM Cd, indicating that this compound is necessary for redox cellular homeostasis. The different responses observed with Cd and Hg treatments might be the basis for specific stress bioindicators.
PB Elsevier
SN 0045-6535
YR 2009
FD 2009
LK https://hdl.handle.net/20.500.14352/99663
UL https://hdl.handle.net/20.500.14352/99663
LA eng
NO Sobrino-Plata, Juan, et al. «Differential Alterations of Antioxidant Defenses as Bioindicators of Mercury and Cadmium Toxicity in Alfalfa». Chemosphere, vol. 77, n.o 7, noviembre de 2009, pp. 946-54. https://doi.org/10.1016/j.chemosphere.2009.08.007.
NO We gratefully appreciate Fundación Ramón Areces for supporting LEH’s laboratory research. This work was also funded by the Spanish Ministry of Science and Innovation (CTM2005-04809/TECNO; REUSA), Comunidad de Madrid (S-0505/AMB/000296, Consorcio EIADES) and Junta de Comunidades de Castilla-La Mancha (PBI07-0091-3644; FITOALMA). COV was supported by a PhD Student Exchange Program Grant provided by Universidad Autónoma de Madrid. We are utterly indebted to Drs. Javier Abadía and Ana Álvarez for supporting us with the analyses of GSH/GSSG, hGSH/hGSSGh and AA by HPLC mass spectrometry at Estación Experimental de Aula Dei-CSIC (Saragossa, Spain).
NO Universidad Autónoma de Madrid
NO Ministerio de Ciencia e Innovación (España)
NO Comunidad de Madrid
NO Junta de Comunidades de Castilla-La Mancha
DS Docta Complutense
RD 11 abr 2025