Hemin (
ferroprotoporphyrin IX), a compound derivative of
heme, has been shown to exert numerous beneficial physiological functions in the resistance of plant to various abiotic stresses. This work investigated the effects of
hemin on ameliorating Cd toxicity in Chinese cabbage (Brassica chinensis L.). Our results showed that leaf
chlorosis, growth inhibition, root morphology and photosynthetic activity were significantly improved by the addition of
hemin in Cd-stressed plants. Meanwhile, Cd-induced oxidative damage was also alleviated by
hemin, which was supported by the decreased level of
malondialdehyde (MDA) in roots of the seedlings treated with
hemin. In the same time, the activities of antioxidative
enzymes, including
superoxide dismutase (SOD),
peroxidase (POD) and
catalase (CAT), as well as the concentrations of
ascorbic acid (AsA) and
glutathione (GSH) were elevated by
hemin, which contributed to the scavenging of Cd-elicited H2O2 and O2•- within the roots of Chinese cabbage seedlings. Furthermore, compared with Cd stressed plants, Cd concentrations in both shoots and roots were markedly decreased by exogenous
hemin. Hence, it can be speculated that
hemin-mediated tolerance to Cd stress may be associated with the inhibition of Cd uptake in Chinese cabbage. This hypothesis was supported by the down-regulated expressions of transporter genes, including BcIRT1, BcIRT2, BcNramp1 and BcZIP2 caused by
hemin addition in Chinese cabbage seedlings under Cd treatment. Taken together, these results suggested that
hemin alleviated Cd toxicity probably through increasing antioxidative capacities and inhibiting Cd uptake of Chinese cabbage.