Absorption, Translocation and Transformation of Arsenic in Medicinal Herb Panax notoginseng-Soil System

In the present study, arsenic in soil and Panax notoginseng was analyzed with the high performance liquid chromatography-atomic fluorescence (HPLC-HG-AFS), for total and species arsenic in an attempt to determine how the plant adsorbs, translocates and transforms arsenic. Results show that inorganic arsenateAs(Ⅴ) and arseniteAs(Ⅲ) were the main forms in P. notoginseng growing soil, and As (Ⅴ) was much higher than As (Ⅲ) in content, accounts for about 95% of the total. Arsenic distributed unevenly in the plant and the tissues of a plant displayed an order of branch root >rhizome >taproot >leaves >stems in terms of content of total arsenic, showing that roots is the main pathway of arsenic flowing from soil to P. notoginseng plant. The distribution of arsenic also varied with speciesAs (Ⅴ), As (Ⅲ) and MMA and plant tissue. For As (Ⅲ), an order of leaves >branch root >rhizome >stems >taproot; for As (Ⅴ), an order of rhizome >branch root >taproot >leaves >stems and for MMA an order of root >stems >rhizome >leaves >taproot was found. Therefore, to reduce bioavailability of the arsenic in soil and to study in depth how to regulate transformation of arsenic between speciesAs (Ⅴ), As (Ⅲ) and MMA in different parts of P. notoginseng are the important ways to mitigate the hazard on safety caused by arsenic in P. notoginseng.