锰对超富集植物青葙镉积累的影响

为探讨锰对青葙吸收和积累镉的影响,通过水培试验和土培试验两种方式,分别在镉处理为0(对照)、0.6、1、2 mg·L~(-1)和0(对照)、3、5、10 mg·kg~(-1)的条件下,施加100 mg·L~(-1)和500 mg·kg~(-1)的锰研究了锰对青葙吸收和积累镉的影响,并且在土培试验进行的同时监测土壤溶液中的镉含量。结果表明,在水培和土培条件下施加锰对青葙吸收和积累镉的作用不同。在水培条件下,向镉处理组中施加锰可显著抑制青葙对镉的吸收和积累。当镉处理浓度为0.6 mg·L~(-1)时,施加锰使青葙叶片镉含量降低了35.9%。然而,在土培条件下,施加锰显著促进了青葙对镉的吸收和积累。在镉处理浓度为3 mg·kg~(-1)时,锰对青葙镉积累促进作用最强,与未施加锰处理组相比青葙叶片中镉含量增加了352%。土壤溶液中镉含量较低,但锰的施加可显著提高土壤溶液中的镉含量(P0.05)。上述结果表明,尽管镉和锰在青葙中可能存在部分相同的转运和吸收途径,但由于两者在土壤固相与液相之间存在的离子交换作用使得土培和水培实验表现出相反的趋势。

Effect of manganese on cadmium accumulation in Celosia argentea Linn., a hyperaccumulator

To explore the effects of Mn on the uptake and accumulation of Cd in Celosia argentea Linn., a hydroponic experiment (with Cd treatments of 0, 0.6, 1, and 2 mg·L^-1) and a soil culture experiment (with Cd treatments of 0, 3, 5, and 10 mg·kg^-1) were conducted with, and without Mn application (100 mg·L^-1 for the hydroponic experiment and 500 mg·kg^-1 for the soil experiment). In addition, Cd concentrations in soil solutions were also tested during the soil culture experiment. The results showed that the effect of Mn on Cd uptake and accumulation in C. argentea differed between the hydroponic and soil experiments. In the hydroponic experiments, application of Mn significantly reduced the uptake and accumulation of Cd in C. argentea. At a Cd treatment of 0.6 mg·L^-1, the application of Mn decreased Cd in the leaves by 35.9%. In soil culture experiments, however, applying Mn significantly enhanced the uptake and accumulation of Cd in C. argentea. When soil Cd was 3 mg·kg^-1, the application of Mn increased Cd concentrations in leaves by 352% when compared with the control. The application of Mn significantly increased the Cd concentrations in the soil solution (P<0.05), although the concentrations of Cd in the soil solutions were relatively low. The inhibiting effect of Mn on Cd uptake in hydroponic experiment indicated that Cd and Mn may share some uptake and transport pathways in the C. argentea. By contrast, a promoting effect of Mn on Cd uptake was observed in the soil experiment due to their ion exchange behaviour in the soil. The application of Mn promoted the release of Cd from the soil into the soil solution, thereby increasing the uptake of Cd by plant roots.