Biochemical studies on amelioration of phytotoxic effects of chromium (VI) in clusterbean [Cyamopsis tetragonoloba (L.) Taub.]
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Date
2013
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CCSHAU
Abstract
Heavy metals are the intrinsic component of the environment with both essential and non essential 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 had been done to study the effect of amelioration of toxic effect of Cr (VI) on morphological and biochemical parameters of clusterbean plants. The crop was raised in pots filled with sandy loam soil in naturally lit net house. The soil in each pot treated with 0.0, 0.5, 1.0, 2.0 and 4.0 mg Cr (VI) kg-1 soil. Morphological parameters like plant height, number of leaves, root length, fresh and dry weight of leaves, stem and root decreased with an increase in the chromium concentration. Growth of clusterbean plants was reduced very significantly in presence of 2 mg Cr (VI) kg-1 soil. The chlorophyll ‘a’, chlorophyll ‘b’, total chlorophyll, carotenoids content, non-structural carbohydrates, crude protein content and IVDMD decreased, whereas, structural carbohydrates viz. NDF, ADF, cellulose, lignin and silica significantly increased with increasing chromium concentration. Minerals like sodium, chromium content increased with increase in supply of chromium concentration. The iron, zinc and potassium content decreased with increase in chromium concentration. Chromium treatment adversely affect activity of enzymes of nitrogen metabolism viz. nitrogenase, NR, NiR, GS, GDH and GOGAT.To ameliorate toxic effect of
Cr (VI), different sets of plants were treated with salicylic acid and ferrous sulphate–EDTA solution through different modes viz. pre-treatment, soil treatment and foliar spray or both. Loss in growth, biochemical and nutritional parameters of clusterbean plants was recovered to different extent by different treatments with salicylic acid (0.25 and 0.5 mM) and FeSO4-EDTA solution (0.25 mM and 0.5 mM). The recovery in biomass of clusterbean plants was maximum with combined soil pretreatment and foliar application of 0.50 FeSO4-EDTA solution. In current study, salicylic acid application by different modes also emerged as a potential way to ameliorate Cr toxicity from economically important crops or plants.
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Keywords
Clusterbean, Cr toxicity, Morphology parameters, Amelioration, Nitrogen
metabolism