Micropropagated plants were generated from canola plant (Brassica napus L.) under some heavy metals stress to assess their responses to different concentrations of Ni, Co, and Pb. The exposure to different metal concentrations induced reductions in shoot and root length, as well as their fresh and dry weights. In addition, chlorophylls a and b and carotenoid contents were reduced. Such reductions were concomitant with increases in total soluble sugars, proline, malondialdehyde (MDA), ascorbic acid (ASA), reduced glutathione (GSH), and total phenol contents. Moreover, the activities of catalase (CAT), superoxide dismutase (SOD), polyphenol oxidase (PPO), and ascorbate peroxidase (APX) were increased in micropropagated plants parallel with decreases in peroxidase (POX) and ascorbate oxidase (ASO) activities. The present data indicated that micropropagated plants grown under heavy metal stress are capable to tolerate and reduce the uptake and translocation of Ni, Co, and Pb elements.
Key words: Brassica napus micropropagation, metal stress, Ni, Co, Pb, antioxidant enzymes
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