药用植物三七对土壤中砷的吸收运转及形态转化

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

  • 摘要: 以栽培药用植物三七(Panax notoginseng)为主要研究对象,采用高效液相色谱-原子荧光联用(HPLC-HG-AFS)技术,研究了三七产地土壤及植株样品中砷(As)含量及其赋存的化学形态,以及三七对As的吸收运转及形态转化。结果表明,无机态的As(Ⅴ)和As(Ⅲ)是三七种植土壤中的主要赋存形态,且As(Ⅴ)含量远高于As(Ⅲ),约占总量的95%。三七植株中总As的分布规律表现为根条 >剪口 >主根 >叶 >茎,说明根部吸收是土壤As进入三七的主要途径;而三七植株中各形态As分布规律因植株部位的不同而存在较大差异,As(Ⅲ):叶 >根条 >剪口 >茎 >主根;As(Ⅴ):剪口 >根条 >主根 >叶 >茎;二甲基砷(MMA):根条 >茎 >剪口 >叶 >主根。降低三七种植土壤As的生物有效性,深入研究As(Ⅴ)、As(Ⅲ)和MMA在三七不同部位相互转化的调控机制是缓解三七As毒害的重要途径。

     

    Abstract: 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.

     

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