砷胁迫下磷对三七砷的微区及亚细胞组织分布特征的影响

Effects of phosphorus additions on micro- and sub-cellular distribution of As in Panax notoginseng under As stresses

通过同步辐射X射线荧光分析(μ-SRXRF)和亚细胞组分分离技术相结合,从植株各部位微区及亚细胞组分层面揭示了药用植物三七在外源磷素作用下砷吸收累积的分布特征。结果表明:三七的根部和茎部是砷的主要富集部位,添加外源磷素可以有效降低三七根部、茎部和叶片的砷含量,降低幅度分别为47%、80%和33%;三七各部位的亚细胞组分砷的累积量不同,其中细胞液是砷的主要富集组分,具有一定的区隔化作用,但不能有效地减少砷对植物细胞新陈代谢的影响和毒害;外源磷素的加入可以显著降低三七不同部位亚细胞各组分中砷的累积量,其降低幅度由高到低依次为细胞液>细胞壁>细胞器,但分析表明,外源磷素的添加对三七各部位的亚细胞组分砷累积量占植株总砷累积量比例的影响不大。

Panax notoginseng（Burk.）F. H. Chen is one of the traditional precious herbal medicines in China. Arsenic（As）pollution in P.notoginseng has attracted wide attention. In this study, we examined the effects of phosphorus additions on micro- and sub- cellular distribution of As in P. notoginseng using synchrotron radiation X-ray fluorescence（SRXRF）and subcellular separation methods. Results showed that large amounts of As was accumulated in roots and stems. Exogenous phosphorus effectively reduced As concentrations in roots, stems and leaves by 47%, 80% and 33%, respectively. The amount of As accumulation was different in different parts of subcellular components.Cytochylema was the main component of As enrichment, showing As compartmentation. However, such compartmentation did not effectively reduce As toxicity to plant cell metabolism. Additions of phosphorus significantly decreased the accumulation of As in various components,in order of cytochylema〉cytoderm〉organelle, but had little effect on the ratios of As in subcellular components to total As.