Performance of
B. napus
in phytoextraction—
an in situ environment friendly technique for the cleanup of
contaminated soils—was evaluated through its response to
cadmium (Cd) toxicity in combination with a chelator
ethylenediamminetetraacetic acid (EDTA) while growing
hydroponically in greenhouse conditions under three levels
of Cd (0, 10, and 50 µM) and two levels of EDTA (0 and
2.5 mM). Cadmium presence decreased plant growth,
biomass and chlorophyll concentrations, while the application
of EDTA enhanced plant growth by reducing Cd-induced
effects in Cd-stressed plants. Addition of EDTA
improved the net photosynthetic and gas exchange capacity
of plants under Cd stress. Presence of Cd at 10 and 50 µM
significantly increased electrolyte leakage, the production
of hydrogen peroxidase (H
2O
2) and malondialdehyde
(MDA) resulting into a significant reduction in the activities
of catalase, guaiacol peroxidase, ascorbate peroxidase
and superoxide dismutase in Cd-stressed plants. Application
of EDTA at the rate of 2.5 mM alone and with combination
of Cd increased the antioxidant enzymes activities
and reduced the electrolyte leakage and production of H
2O
2
and MDA. The
B. napus actively accumulated Cd when
applied with EDTA in roots, stems and leaves viz. 2817,
2207 and 1238 mg kg
-1 DW, respectively, at higher Cd
level (50 µM) followed by lower level of Cd (10 µM) viz.
1704, 1366 and 763 mg kg
-1 DW, respectively. Results
showed that this technique could be useful for the remediation
of heavy metal-contaminated agricultural and
industrial soils.
