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.