Total mercury accumulation in aboveground parts of maize plants (<i>Zea mays</i>) throughout a growing season

We investigated Hg accumulation in maize (<i>Zea mays</i>) plants grown in non-contaminated conditions on a farm in Switzerland throughout a growing season. Concentrations of Hg in leaves and husk followed the same temporal pattern as the mass growth of these parts. In contrast, silk and tassel accumulated Hg almost linearly over time until harvest. At the end of the growing season Hg concentration was highest in tassel (10.4 ng g⁻¹), followed by leaves (7.3 ng g⁻¹) and silk (5.7 ng g⁻¹). Silk and tassel had accumulated 5–10 times more Hg per unit dry mass than all aboveground parts of the plant on average. Cob and kernels contained only very small amounts of Hg. Greater exposure of a plant part to the atmosphere was clearly associated with higher rates of Hg accumulation.

本研究针对瑞士某农场无污染种植环境下的玉米（<i>Zea mays</i>），对其整个生长季内的汞（Hg）累积特征展开了调查。玉米叶片与苞壳的汞浓度随时间变化的模式与其生物量增长模式一致。与之相反，花丝与雄穗的汞累积量随时间几乎呈线性增长，直至收获。生长季结束时，雄穗的汞浓度最高，达10.4 ng g⁻¹，其次为叶片（7.3 ng g⁻¹）与花丝（5.7 ng g⁻¹）。平均而言，花丝与雄穗单位干重的汞累积量是植株所有地上部分的5至10倍。玉米穗轴与籽粒中的汞含量极低。植株器官与大气的接触程度越高，其汞累积速率也明显越快。