Chromium stress in <i>Brassica juncea</i> L. cv. 'Pusa Jai Kissan' under hydroponic culture

Abstract

Chromium (Cr) entering plant tissue inhibits most physiological processes at all levels of metabolism including inhibition of growth, photosynthesis and nitrate assimilation. Since Cr exists in many forms, its toxicity to plants depends on its valence state, with Cr (VI) found to be highly toxic and mobile than Cr (III). Different concentrations of Cr (0, 25, 50 and 100 μM) in the form of K₂Cr₂O₇ was added to 30 days old Brassica juncea plant and harvested on the 3rd and 5th days after treatment for estimation of plant growth, chlorophyll, total soluble protein, free amino acids and nitrate reductase activity. Cr was found to cause deleterious effects on whole plant growth. The potential of plants with the capacity to accumulate or to stabilize Cr compounds for bioremediation of Cr contamination has gained interest in recent years. The biochemical aspects like photosynthetic pigments (Chl a and Chl b), total protein and amino acids content decreased with Cr concentration. A significant increase in nitrate reductase activity was observed corresponding to Cr concentration.

Key words: Brassica juncea, chromium, heavy metal, phytoremediation.