Journal of Environmental Biology

Chromium-induced alterations in photosynthesis and

associated attributes in Indian mustard

Author Details

Hema Diwan

Molecular Ecology Laboratory, Department of Botany, Faculty of Science, Hamdard University,

New Delhi - 110 062, India

Altaf Ahmad

Molecular Ecology Laboratory, Department of Botany, Faculty of Science, Hamdard University,

New Delhi - 110 062, India

Muhammad Iqbal

(Corresponding author)

Molecular Ecology Laboratory, Department of Botany, Faculty of Science, Hamdard University,

New Delhi - 110 062, India

Department of Plant Production, College of Food and Agricultural Sciences, King Saud University,

Riyadh – 11451, Saudi Arabia

e-mail: iqbalg5@yahoo.co.in

Publication Data

Paper received:

07 May 2010

Revised received:

10 December 2010

Accepted:

08 January 2011

Abstract

Contamination of soil and water by chromium (Cr) is increasing enormously due to anthropogenic activities. The potential of plants to accumulate or stabilize Cr compounds for the purpose of remediation of Cr contamination has been recognized in recent years. We conducted pot experiments to study photosynthesis and associated attributes in cv Pusa Jai Kisan of Indian mustard under natural as well as Cr-loaded environmental conditions. High doses of Cr caused toxic effects in plants, as evident by a reduction in photosynthetic rate (24.3 to 8.7 µmol CO₂ m^-2 s^-1 at 80 DAS), nitrate reductase activity (3.76 to 1.30 µmol nitrite g^-1 f. wt. h^-1 at 80 DAS) and the contents of chlorophyll (1.49 to 0.86 mg g^-1 f. wt. at 80 DAS) and soluble protein (2.96 to 1.93 mg g^-1 f. wt. at 80 DAS). Since plants lack a specific Cr-transport system, mineral nutrient contents also changed due to Cr toxicity. Cr accumulation in different plant parts was affected by both duration and dose of Cr treatments, with a maximal localization of Cr in roots (up to 0.77 mg g^-1 d. wt) at initial stages (40 DAS) and in stem (up to 4.19 mg g^-1 d. wt) at the later stage (80 DAS) of plant growth. Thus, Indian mustard was able to withstand Cr stress and protect itself from Cr toxicity by altering various metabolic processes. Owing to its ability to accumulate large amounts of Cr, it may be useful in the process of land reclamation.

Key words

Chlorophyll, Chromium, Indian mustard, Nitrate reductase, Phytotoxicity, Phytoremediation

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