缺Fe对水稻根际Fe、Cd吸附与根系吸收的影响

Effects of rhizospheric conditions under iron deficiency on Cd and Fe adsorption on the vermiculite/root surface and their uptake by rice were investigated using nutrient solution and vermiculite culture. Results showed that compared with normal Fe nutrition level, acidity and reducing condition in the rice rhizosphere under Fe deficiency was stronger, which might increase the dissolved Cd and Fe concentration. Noncrystalline Fe concentration on the vermiculite surface was also higher under Fe deficiency, not only leading to more soluble Fe(II) to allievate Fe deficiency stress but also bringing more EXC-Cd adsorption on the vermiculite surface. Besides, Fe adsorption on rice root Fe plaque was decreased, resulting in less competition with Cd adsorption on Fe plaque, and further leading to more Cd adsorption on root Fe plaque. Both Cd2+ and Fe2+ uptake by rice roots were higher under Fe deficiency, which might be due to the secretion of low weight molecule organic acids (LWMOAs) and phytosiderophores. These compounds could not only acidity rice rhizosphere but also chelate with Fe and Cd, making higher translocation of these two elements in the rhizosphere.