Antioxidative response of metal-accumulator and non-accumulator plants under cadmium stress
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- Wang, Z., Zhang, Y., Huang, Z. et al. Plant Soil (2008) 310: 137. doi:10.1007/s11104-008-9641-1
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The present study aims to elucidate the role of antioxidative enzyme in the adaptive responses of metal-accumulators (Thlaspi caerulescens and Brassica juncea) and non-accumulator plant (Nicotiana tabacum) to Cadmium stress. When seedlings of plants were grown in hydroponic condition for a period of 4 days in the presence of 200 or 400 μM CdCl2, photosynthetic rate, transpiration rate and stomatal conductance in metal-accumulators decreased more slowly than that in tobacco. MDA content and electrolyte leakage increased with elevated Cd concentration and exposure time in all plant species, while the oxidative damage in tobacco was more serious than that in metal-accumulators. The activities of SOD and CAT in metal-accumulators were significantly higher than that in tobacco under normal condition, whereas there was no significant difference in the activity of POD between Indian mustard and tobacco. The activities of antioxidative enzymes increased rapidly in metal-accumulators in response to the Cd treatments, especially SOD and CAT. In tobacco, CAT activity declined rapidly by exposure to the Cd treatment, though the activity of SOD and POD was enhanced, indicating that the antioxidative enzymes in tobacco could not fully scavenge ROS generated by Cd toxicity. These results collectively indicate that the enzymatic antioxidation capacity is one of the important mechanisms responsible for metal tolerance in metal-accumulator plant species.
KeywordsAntioxidative enzyme Brassica juncea Cadmium Heavy metal tolerance Nicotiana tabacum Thlaspi caerulescens
reactive oxygen species