Lead Accumulation and its Effects on Growth and Biochemical Parameters in Tagetes erecta L

Abstract

Tagetes erecta L. was raised in pots containing soil treated with various concentrations of Pb(NO3)2 (500, 1000, 1500, 2000 and 2500mg/kg). At maturity plants were separated into root, stem, leaves and inflorescence and lead accumulated in each part was quantified. The effects of lead accumulation on growth was analyzed by the measurement of various growth parameters like root and shoot length, fresh and dry weight of root and shoot and total leaf area per plant. Moreover effect of lead accumulation on biochemical parameters was checked by quantitative estimation of various biochemical parameters like chlorophyll, total protein, free amino acids, total sugar, reducing sugar and starch. Results showed that there is no remarkable negative effect of accumulation of lead on the morphological growth of the plant. Biochemical analysis showed that amount of total protein continuously decreased whereas that of free amino acids continuously increased with increasing concentrations of lead. Amount of chlorophyll, total sugar, reducing sugar and starch contents continuously increased till mid-level i.e., Pb 1500 mg/kg and then continuously decreased at higher concentrations. Results of quantitative estimation of Pb in root, stem, leaves and inflorescence showed that roots accumulated highest amount of Pb followed by stem and leaves, whereas inflorescence contained least amount of Pb. Key-wordsLead (Pb), Heavy metal, Tagetes erecta L., Accumulation, Phytoremediation INTRODUCTION Heavy metal pollution is one of the severe problems faced by the world today. As a consequence of the industrial revolution there is an enormous and increasing demand for heavy metals that leads to high anthropogenic emission of heavy metals in the biosphere. Their accumulation in soil becomes dangerous to all kind of organisms including plants. These are a unique class of toxicants since they cannot be broken down to non-toxic forms easily. Metals like Pb, Hg, Cd, Ar, and Cr have no biological function and are toxic to life even at very low concentration. Lead is a potentially toxic heavy metal with characteristic toxic action and is the main source of environmental pollution. Lead is one of the potentially toxic heavy metal pollutants of the environment with no known biological function and its concentrations are rapidly increased in Access this article online Quick Response Code Website: