[Effects of exogenous proline on the growth of wheat seedlings under cadmium stress]

Taking high protein wheat variety 'Beinong 9549' as test material, this paper studied the effects of foliage-spraying different concentration (0, 1.0, 5.0 and 10.0 mmol x L(-1)) proline on the growth and heavy metal uptake of wheat seedlings under cadmium stress. Under the stress of 1.0 mmol x L(-1) of CdCl2, the root length, plant height and dry mass, leaf chlorophyll a and b and carotenoid contents of the seedlings decreased significantly by 24.0%, 15.0%, 27.5%, 23.3%, 6.7% and 30.8%, respectively, the leaf superoxide dismutase (SOD) activity decreased by 18.4%, the leaf proline, ascorbic acid and malondialdehyde (MDA) contents and the membrane permeability increased significantly by 78.6%, 31.5%, 17.9% and 24.8%, respectively, the leaf peroxidase (POD) activity was 2.4 folds higher, and the Cu uptake was promoted while the Zu absorption was inhibited, compared with the control. With the increasing concentration of sprayed proline, the root length, plant height and dry mass, and leaf chlorophyll a and b and carotenoid contents increased gradually to the levels of the control, the leaf proline and ascorbic acid contents and the leaf SOD activity increased, the leaf soluble protein content decreased after an initial increase, the leaf POD activity, MDA content and membrane permeability decreased, and the Zn accumulation increased while the Cd and Cu accumulation decreased. In sum, foliage-spraying proline could alleviate the cadmium stress on the growth of wheat seedlings, and spraying 5.0-10.0 mmol x L(-1) of proline could obtain the best effect.