镉在南美蟛蜞菊、蟛蜞菊及其杂交种中的迁移和分布特征

Migration and Distribution Characteristics of Cadmium in Sphagneticola trilobata, S. calendulacea and Their Hybrid

摘要:

为了解植物对镉的吸收和迁移特性，用200 μmol/L镉处理蟛蜞菊（Sphagneticola calendulacea）、南美蟛蜞菊（S.trilobata）及其杂交种，研究了其对镉的吸收、迁移与分布的差异。结果表明，随着镉处理时间的延长，3种植物茎和叶中的镉含量逐渐上升，叶片的镉含量逐渐与茎相当，而根部的镉含量一直是最高的；整株水平上，杂交种的镉含量一直是最高的。恢复生长后，3种植物根中镉含量均呈下降趋势，杂交种（50.4%）>蟛蜞菊（35.8%）>南美蟛蜞菊（33.7%）。镉在3种植物的叶位分布模式在去镉前后没有明显的变化，杂交种更偏向将重金属镉积累于幼叶和成熟叶中。3种植物从叶脉、叶脉间隙到叶片边缘的镉含量逐渐下降，南美蟛蜞菊叶脉的镉含量（2 766.3 μg/kg）最高。可见，杂交种对镉的吸收和转运转移能力高于双亲，预示其在未来应用于植物修复中具有更大的潜力。

Abstract:

In order to understand the migration and absorption characteristics of cadmium, the differences in absorption, migration and distribution of cadmium were studied in Sphagneticola calendulacea (indigenous congener), S. trilobata (alien invasive species) and their hybrid treated with Hoagland solution containing 200 μmol/L CdCl₂. The results showed that the cadmium concentrations in stems and leaves of three species gradually increased with the time extension of cadmium treatment, and the cadmium concentrations in leaves gradually matched that in stems, while that in roots of three species was always the highest. For the whole plant, cadmium concentration of the hybrid was also the highest under stress. After recovery growth, the cadmium concentrations in roots of hybrid, S. calendulacea, and S. trilobata declined by 50.4%, 35.8%, and 33.7%, respectively. Distribution pattern of cadmium in leaves of three species had not significant change treated with/without CdCl₂. The hybrid tended to accumulate cadmium in young and mature leaves. The cadmium concentrations gradually decreased from vein, internal vein and leaf edge of three species, which in internal vein of S. trilobata was the highest (2 766.3 μg/kg). Therefore, the hybrid displayed stronger ability to absorb, transport and transfer cadmium than its parents, suggesting that it had greater potential in phytoremediation in the future.