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Reactive oxygen species (ROS) scavengers, including ascorbate peroxidase, superoxide dismutase, catalase and peroxidase, are the most commonly used biomarkers in assessing an organisms’ response to many biotic and abiotic stresses. In this study, we cloned an 866 bp GST(phi) gene in Lemna minorand investigated its characteristics, expression and enzymatic activities under 75 μM cadmium concentrations in comparison with other ROS scavengers. GST(phi) gene expression patterns were similar to those of other scavengers of ROS. This suggests that GST(phi) might be involved in responding to heavy metal (cadmium) stress and that its expression level could be used as a bio-indicator in monitoring cadmium pollution.

The chenopodiaceae Suaeda salsaL. is a leaf succulent euhalophyte. Shoots of the S. salsaare larger and more succulent when grown in highly saline environments. This increased growth and water uptake has been correlated with a large and specific cellular accumulation of sodium. S. salsadoes not have salt glands or salt bladders on its leaves. Thus, this plant must compartmentalize the toxic Na+in the vacuoles. The ability to compartmentalize sodium may result from a stimulation of the proton pumps that provide the driving force for increased sodium transport into the vacuole. In this work, we isolated the cDNA of the vacuolar membrane proton-translocating inorganic pyrophosphatase (H+-PPase) from S. salsa. The SsVPcDNA contains an uninterrupted open reading frame of 2292 bp, coding for a polypeptide of 764 amino acids. Northern blotting analysis showed that SsVPwas induced in salinity treated leaves. The activities of both the V-ATPase and the V-PPase in Arabidopsisoverexpressing SsVP-2 is higher markedly than in wild-type plant under 200 mM NaCl and drought stresses. The Overexpression of SsVPcan increase salt and drought tolerance of transgenic Arabidopsis.The chenopodiaceae Suaeda salsaL. is a leaf succulent euhalophyte. Shoots of the S. salsaare larger and more succulent when grown in highly saline environments. This increased growth and water uptake has been correlated with a large and specific cellular accumulation of sodium. S. salsadoes not have salt glands or salt bladders on its leaves. Thus, this plant must compartmentalize the toxic Na+in the vacuoles. The ability to compartmentalize sodium may result from a stimulation of the proton pumps that provide the driving force for increased sodium transport into the vacuole. In this work, we isolated the cDNA of the vacuolar membrane proton-translocating inorganic pyrophosphatase (H+-PPase) from S. salsa. The SsVPcDNA contains an uninterrupted open reading frame of 2292 bp, coding for a polypeptide of 764 amino acids. Northern blotting analysis showed that SsVPwas induced in salinity treated leaves. The activities of both the V-ATPase and the V-PPase in Arabidopsisoverexpressing SsVP-2 is higher markedly than in wild-type plant under 200 mM NaCl and drought stresses. The Overexpression of SsVPcan increase salt and drought tolerance of transgenic Arabidopsis.