Effect of Chromium(VI) Toxicity on Enzymes of Nitrogen Metabolism in Clusterbean (Cyamopsis tetragonoloba L.).

Punesh Sangwan,Vinod Kumar,U N Joshi

doi:10.1155/2014/784036

Abstract

Heavy metals are the intrinsic component of the environment with both essential and nonessential types. Their excessive levels pose a threat to plant growth and yield. Also, some heavy metals are toxic to plants even at very low concentrations. The present investigation (a pot experiment) was conducted to determine the affects of varying chromium(VI) levels (0.0, 0.5, 1.0, 2.0, and 4.0 mg chromium(VI) kg−1 soil in the form of potassium dichromate) on the key enzymes of nitrogen metabolism in clusterbean. Chromium treatment adversely affect nitrogenase, nitrate reductase, nitrite reductase, glutamine synthetase, and glutamate dehydrogenase in various plant organs at different growth stages as specific enzyme activity of these enzymes decreased with an increase in chromium(VI) levels from 0 to 2.0 mg chromium(VI) kg−1 soil and 4.0 mg chromium(VI) kg−1 soil was found to be lethal to clusterbean plants. In general, the enzyme activity increased with advancement of growth to reach maximum at flowering stage and thereafter decreased at grain filling stage.

Highlights

Excessive levels of heavy metals in agricultural lands constitute an increasingly serious threat for intact plant growth and yield and for the environment and human health [1]
The toxicity of plants due to heavy metals, on agricultural economic crops, presents a challenge to plant scientists concerned with yield and quality in crop production [2]
Contamination of the environment by Cr has become a major concern and its toxicity to plants depends on its valence state with Cr(VI) being highly toxic and mobile than Cr(III) [6]

Summary

Introduction

Excessive levels of heavy metals in agricultural lands constitute an increasingly serious threat for intact plant growth and yield and for the environment and human health [1]. The toxicity of plants due to heavy metals, on agricultural economic crops, presents a challenge to plant scientists concerned with yield and quality in crop production [2] These metals retard farming efficiency and destroy the health of the plants and animals [3]. Some heavy metals such as chromium (Cr), lead (Pb), mercury (Hg), and cadmium (Cd), especially in large amounts, could affect growth and productivity of plants [4]. Cr(III) occurs naturally in the environment and is an essential nutrient, whereas Cr(VI) is generally produced by industrial processes [7]. Significant quantities of Cr are added to soil by the disposal of fly ash as well as phosphatic fertilizer application [10]

Methods

Results

Conclusion