Phytotoxic effects of Heavy metals (Cr, Cd, Mn and Zn) on Wheat (Triticum aestivum L.) Seed Germination and Seedlings growth in Black Cotton Soil of Nanded, India

To assess the phytotoxicity of chromium (Cr), cadmium (Cd), manganese (Mn) and zinc (Zn) to wheat, experiments were carried out in Black Cotton soil (of Nanded city, India) fed with different aqueous concentrations (2, 4, 6, 8 and 10 mg/L) of aforementioned metal ions over the period of eight consecutive days. The phytotoxic effects on seed germination, root, shoot, seedling growth, seedling vigor index, tolerance indices of wheat (Triticum aestivum L.) were studied. All results, when compared to control, show heavy metals adversely affecting the normal growth of plants by reducing seed germination and decreasing root and shoot length. The toxic effects of selected heavy metals to seed germination can be arranged in the rank order of inhibition as: Zn>Cd>Mn>Cr. The toxicity of all heavy metals to young seedlings was found similar to seeds and their effects on seedlings increase with their increased concentrations in the aqueous medium or soil ecosystem. The present results thus exemplify a model system to screen for various concentrations of heavy metals for their phytotoxic effects and also screen for the seeds able to counteract the deleterious effects of such heavy metals in various types of irrigation waters and agricultural soils.