锌镉互作对水稻幼苗镉和矿物质积累的影响

研究分析了在浓度梯度的Zn×Cd胁迫下两个水稻品种黄华占和IR68144幼苗根部和地上部Cd和矿物质的积累特征.结果表明:(1)随着营养液Cd2+浓度的上升,黄华占和IR68144根部和地上部的Cd含量都大幅增加.中等浓度的Zn2+能有效地减少高浓度Cd胁迫时水稻根系对Cd的吸收,但低浓度Cd胁迫时表现为协同吸收,而高浓度Zn2+则主要促进Cd的吸收.中等浓度的Z2++在一定条件下也能有效减少水稻地上部的Cd积累量,但其作用与Cd2+浓度和水稻基因型都有关,而高浓度Zn2+则完全表现为促进Cd的积累.(2)黄华占和IR68144根部和地上部的Zn含量都随着营养液Zn2+浓度的提高而增加.Cd对水稻Zn积累的影响与Zn2+浓度和基因型都有关,但大多数情况下Cd胁迫明显降低了水稻对Zn的积累.(3)在正常Zn2+浓度(0μmol/L)营养液中,Cd2+浓度上升时,黄华占和IR68144根部Fe积累量都保持相对平稳,但两者地上部Fe积累量明显持续降低;两品种根部Mn含量都不断增加,但黄华占地上部Mn积累量持续下降,而IR68144中保持平稳.Zn×Cd互作对水稻Fe积累的影响在根部主要表现为促进作用,在地上部则主要显示出抑制作用,但两品种的Mn积累量表现出复杂的Cd2+、Zn2+浓度和基因型相关性.说明锌镉互作能有效调控水稻幼苗对镉的吸收与转运,但其互作效应与Zn2+和Cd2+浓度有关,且表现出明显的基因型差异;同时还改变了水稻幼苗中锌、铁、锰等的积累.

Effects of Zn and Cd Interaction on Cd and mineral elements accumulation in rice seedlings

The accumulative characteristics of Cadmium (Cd) and mineral elements in roots and shoots of Huanghuazhan and IR68144 seedlings under gradient Zinc (Zn) Cd stress were studied. The results were as follows:(1) With the rising of Cd2+ concentration in nutrient solution, Cd content of Huanghuazhan and IR68144 roots and shoots increased significantly. The absorption of Cd in rice roots was effectively reduced by moderate concentration of Zn2+ at high concentration of Cd stress, but they showed synergistic absorption at low concentration of Cd stress. However, a high concentration of Zn2+ promoted the absorption of Cd mainly. Rice shoots Cd accumulation could also be reduced effectively by moderate concentrations of Zn2+ under certain conditions, but its role depended on the concentration of Cd2+ and rice genotype. Nevertheless, high concentration of Zn2+ promoted the accumulation of Cd inall cases. (2) Zn content of roots and shoots from Huanghuazhan and IR68144 rose along with the increase of Zn2+ concentration in the nutrient solution. The effect of Cd on Zn accumulation was related to Zn2+ concentration and ricegenotype, but in most cases the accumulation of Zn in rice reduced significantly under Cd stress. (3) In the nutrient solution with normal Zn2+ concentration (0M/L), along with the increase of Cd2+ concentration, Fe accumulation in Huanghuazhan and IR68144 roots kept relatively stable, but it significantly reduced in shoots of both cultivars. At the same conditions, Mn content of roots from the two varieties increased, but that of Huanghuazhan shoot declined continuously while kept balance in IR68144. Zn Cd interaction on Fe accumulation mainly performed promoting effect in the roots, and chiefly showed inhibitory effect in shoots, but their effects on Mn accumulation were related to Cd2+, Zn2+ concentration and rice genotype complicatedly. Zn Cd interaction could effectively control the absorption and transport of cadmium in rice seedlings, but the interaction effects associated with Zn2+ and Cd2+ concentration in the nutrient solution, and showed a significant genotypic difference. Zn Cd interaction also changed the Zn, Fe and Mn accumulation in rice seedlings.