Constitutive Effects of Distinct Heavy Metals (Cd, Pb and As) on Seed Germination and Physiological Characters of Groundnut (Arachis hypogaea L.)

Heavy metals are carcinogenic in nature, damage DNA, proteins and lipids that adversely affects plant growth and yield. The deterrent heavy metals cadmium, lead and arsenic results in root growth inhibition by accumulation of reactive oxygen species. These cellular derailment results change in antioxidant activity, inhibition of transpiration and photosynthesis, disturbs carbohydrate metabolism, lipid peroxidation leading to secondary stresses like nutrition stress. Groundnut is the king of oil seed crops and is very sensitive to low concentration of heavy metals. The present study deals with the effect of different concentrations of heavy metals on groundnut when applied individually and in combination, the germination rate, root length, shoot length, biomass, seedling vigour index, tolerance index, phyto toxicity and seedling inhibition rate was decreased. Shoots become thick and thin, length and surface area of leaves are reduced and leaf plasticity occurred. Interestingly cd shows different results like increased germination percentage, increased root length, shoot length especially in combination forms at particular concentration levels. The results indicates that heavy metals like Cd, Pb , As, Cd + Pb, Cd + AS, Pb + As and Cd + Pb + As will cause phenotypic changes in groundnut which will leads drastic effects on plant metabolisms which cause crop yield loss and ecological imbalance. Cd alone and in combinational forms shows increased germination rate and root length elongation. This study shows the Cd ability in restoring the plant defects caused by Pb and As.