Antioxidant defence mechanisms in chickpea (Cicer arietinum L.) under copper and arsenic toxicity

Chickpea (Cicer arietinum L.) is one of the oldest pulse crops cultivated from ancient time both in Asia and Europe. India is the largest producer of chickpea in the world, sharing 65 and 70% of production and total global area, respectively. The inhibition of plant growth and crop productivity by excess heavy metals is a global agricultural problem. Therefore, a pot experiment was conducted at wire house of the Department of Plant Physiology, Institute of Agricultural Sciences, Banaras Hindu University, Varanasi during Rabi season of 2009-10, using a complete randomized design with four replications and five treatments. Our experimental findings reveal that excessive amount of copper (Cu) (200 mg/kg) and arsenic (As) (200 mg/kg) in soil caused a mark reduction in nitrate reductase enzyme activity at both growth stages. However, a little increment was found in proline content, peroxidase and superoxide dismutase activity under higher doses of Cu and As at both growth stages. The study aimed to get more information on physiological changes in activity of antioxidant enzymes under heavy metal toxicity. Key words: Antioxidant enzymes, chickpea, heavy metals, nitrate reductase, proline content.