镁、锰、活性炭和石灰及其交互作用对小麦镉吸收的影响

采用盆栽试验,研究了在镉污染土壤上施用石灰、硫酸镁、硫酸锰和活性炭不同用量以及交互作用对小麦生长和吸收重金属镉的影响.研究结果表明,在试验条件下施用适量的硫酸镁、硫酸锰或与石灰配合能明显提高小麦籽粒产量,单施石灰或与活性炭配合施用降低了小麦籽粒产量；与对照(CK)相比,所有处理秸秆产量均下降.施用硫酸镁能显著降低小麦籽粒和秸秆中Cd浓度,且随用量的增加两增大.低量硫酸锰能有效降低小麦籽粒和秸秆中Cd浓度,高量反而增加小麦对Cd的吸收.石灰、活性炭单独施用或配合施用都能明显减少小麦对Cd的吸收,但籽/杆中Cd比却随石灰用量的增加呈明显的上升趋势.叶面喷施硫酸镁对降低小麦吸收镉的效果与土施相当,但叶面喷施硫酸锰却比土施硫酸锰显著降低了小麦籽粒中的镉浓度与吸收量.硫酸镁与硫酸锰,或石灰、硫酸镁和硫酸锰3种物质配合施用,对小麦籽粒镉浓度和吸收量的降低表现出明显的正交互作用,对抑制小麦体内镉从秸秆向籽粒的转移具有显著效果.

Effects of magnesium, manganese, activated carbon and lime and their interactions on cadmium uptake by wheat

A pot experiment was conducted to investigate impact of magnesium (Mg), manganese (Mn), activated carbon and lime and their interactions on wheat growth and cadmium (Cd) uptake from a Cd polluted agricultural soil. Results showed that application of appropriate amounts of magnesium sulfate (Mg), manganese sulfate (Mn) or in combination with lime could promote wheat growth and seed yields, while addition of lime alone or in combination with activated carbon significantly reduced wheat seed yield. Application of Mg significantly reduced concentrations and uptake of Cd in wheat seeds and straw and positively related to Mg rates. Concentrations and uptake of Cd in wheat seeds and straw were effectively decreased by the lower rates of Mn but increased by the higher rates. Lime and activated carbon, no matter it was used alone or together, remarkably restricted Cd uptake by wheat, while Cd ratio of seed/straw tended to increase with lime rates. Folia spray of Mg was equally effective as incorporating Mg into soil on restricting Cd uptake by wheat but a significant depressing effect on Cd uptake by folia spray of Mn over soil application of Mn was observed. Whether Mg and Mn or lime, Mg and Mn were used together produced pronounced positive interactions on depressing Cd concentrations and uptake in wheat seeds and significant restrictive effect on Cd transfer from straw to seeds as well.