土壤溶解性有机质对植物吸收-输送-贮存重金属的影响研究现状与进展

土壤溶解性有机质对重金属生物地球化学循环中的生物可利用性起着重要作用。近年来,在土壤溶解性有机质对植物吸收、输送和贮存重金属过程的影响研究领域,国际上主要聚焦于以下三个探索方向:①土壤溶解性有机质与重金属形成配位体,改变重金属在土壤中的迁移性和植物根际环境的作用机理研究;②土壤溶解性有机质可突破植物细胞内重金属吸附点位的限制,通过控制植物细胞壁-重金属复合体的形态及重金属在细胞壁内外的吸收平衡,来干预重金属穿过细胞壁进入植物体的动力学过程研究;③土壤溶解性有机质-重金属的络合形态影响重金属在植物体内的输送和贮存作用过程与机理研究。本文基于研究溶解性有机质和重金属的植物过程中,水体溶解性有机质研究多而土壤溶解性有机质研究少的现状,针对溶解性有机质异质性的研究难点和溶解性有机质与植物亚细胞结构的配位特征的复杂性与局限性,从极性、官能团、配位结构等角度,分析并评述了土壤溶解性有机质和重金属生物地球化学中,植物吸收、输送和贮存重金属过程的研究现状和未来发展趋势。

Status and Progress of Effects of Dissolved Organic Matter on the Absorption-Transmission-Storage of Heavy Metals in Plants

The dissolved organic matter (DOM) in soil plays an important role in heavy metals biological availability in biogeochemical cycling. In this paper three primary research aspects of how DOM in soil affects plants absorption, transport and storage of heavy metals in recent years are reviewed, namely. (1) the ligand of DOM in soil and heavy metals can change the mobility of heavy metals in the soil and plant rhizosphere. (2) DOM in soil can break the heavy metals adsorption point limit in plant cells, control the form of plant cell wall-heavy metal complexes and the absorption balance of heavy metals both inside and outside the cell wall, which affects the dynamic process of heavy metals crossing through cell walls into plants. (3) the complexation forms of DOM in soil-heavy metals will affect the transport and storage of heavy metals in plants. The current studies of DOM in the water body are more comprehensive than those of DOM in soil. Recognizing the difficulty of heterogeneity of DOM, the complexity and limitation of coordinated features for plant subcellular structures, the research works were evaluated on DOM in soil and heavy metals in the research field of biogeochemistry by the ways of polarity and functional groups, et al. Limitations and future development of DOM in soil are discussed on absorption, transmission and storage of heavy metals in plants.