Antioxidative responses in relation to growth of mustard (Brassica juncea cv. Pusa Jaikisan) plants exposed to hexavalent chromium.
Effect of hexavalent chromium (Cr6+) was seen on Brassica juncea cv. Pusa Jaikisan grown for 15 days in hydroponic culture supplemented with 0.2, 2 and 20 microM Cr. The inhibitory response of Cr6+ on growth of B. juncea was concentration and time dependent. The stimulation of plant growth, observed in response to exposure to 0.2 microM Cr6+, during initial 5 days was reversed on prolonged treatment and at higher Cr6+ concentrations (2 and 20 microM Cr6+). Despite reduction in growth, chlorophyll content increased substantially on 15 days exposure to 20 microM Cr6+. Significant increases in lipid peroxidation and tissue concentration of H2O2 occurred in plants exposed to 2 and 20 microM Cr6+. Effect of Cr6+ on antioxidative enzymes in roots and leaves was differential. SOD and CAT activities at lower levels of Cr6+ supply remained higher all through the treatment. While APX was very susceptible to excess Cr6+, GR and GST increased at elevated levels of Cr6+. The results suggested Cr6+ induced depression in plant growth of B. juncea to be a function of increased cellular accumulation of Cr despite increase in the activities of some of the antioxidative enzymes.
Pandey
Vivek
V
Stress Physiology, National Botanical Research Institute, Rana Pratap Marg, Lucknow 226 001, India. vivekpandey64@yahoo.com
Dixit
Vivek
V
Shyam
Radhey
R
D000975:Antioxidants / Q000502:physiology*; D001937:Brassica / Q000737:chemistry*; D002274:Carcinogens, Environmental / Q000633:toxicity*; D002374:Catalase / Q000378:metabolism; D002857:Chromium / Q000633:toxicity*; D015227:Lipid Peroxidation; D018515:Plant Leaves / Q000201:enzymology; D018517:Plant Roots / Q000201:enzymology; D013482:Superoxide Dismutase / Q000378:metabolism
D000975:Antioxidants; D002274:Carcinogens, Environmental; D002857:Chromium; C074702:chromium hexavalent ion; D002374:Catalase; D013482:Superoxide Dismutase