外源磷素对药用植物三七吸收砷的微区及形态分布特征影响

Effect of Micro and Morphology Distribution of Panax Notoginseng Uptake of Arsenic with Exogenous Phosphorus

三七是中国特有的珍稀药用植物,其生长环境受地域、气候、土壤等条件的限制,仅云南省文山州三七产量高、品质好。但由于矿业开采、工业生产等因素使得土壤砷的背景值超标,逐渐威胁三七的正常生长及其产品质量。因此,如何降低三七砷污染是目前迫切需要解决的问题。磷与砷具有相似的结构和理化性质,利用磷与砷在土壤中的拮抗效应,达到控制土壤砷危害的效果。本研究利用同步辐射X射线荧光方法(SRXRF)和高效液相色谱-原子荧光联用技术(HPLC-HG-AFS)相结合对参试三七植株进行分析测定,从细胞微区组织层面揭示药用植物三七在外源磷素作用下吸收As和P的相对含量分布规律和三七植株各部位的砷形态及含量特征,以及各部位的生物转运系数及富集系数的变化。结果表明:磷和砷在三七主根部的相对含量荧光分析中保持分布规律一致的特性,说明三七根部吸收磷和砷的点位相同;添加外源磷素处理可以有效降低三七各部位三价砷和五价砷的含量,最大降幅达50%,同时可以降低根部对砷的吸收富集系数;试验中仅添加五价砷元素,但在三七植株各部位均检出三价砷,说明三七体内存在着砷还原机制;其中茎部的三价砷的含量均高于五价砷,推测茎是三七体内砷还原反应的主要场所。

Panax Notoginseng is China’s unique rare medicinal plants, its growth environment by region, climate, soil and other conditions, but its only in Wenshan of Yunnan Province have high yield and good quality. However, due to mining, industrial production and other factors, the background value of soil arsenic exceeded, and gradually threatened the normal growth and product quality of P. Notoginseng. Therefore how to reduce arsenic accumulation in P. Notoginseng is urgent. Structurally similar phosphorus and arsenic have similar physical and chemical properties, the use of antagonistic effect of phosphorus and arsenic in the soil, to control soil arsenic hazard effect. This study by synchrotron radiation X-ray fluorescence (μ-SRXRF) method and high performance liquid chromatography-combination of atomic fluorescence spectrometry (HPLC-HG-AFS), from the micro cell tissue area level reveal P. Notoginseng medicinal plants under the effect of exogenous p adsorption of arsenic distribution rule and P. Notoginseng characteristics of arsenic form and content in different parts of the plant, and the change of the biological transport coefficient and the enrichment coefficient of the various parts. The results showed that distribution characteristics of phosphorus and arsenic in the main root of P. Notoginseng fluorescence analysis was the same and description of P. Notoginseng root uptake of phosphorus and arsenic level the same. Addition of exogenous phosphorus treatment can effectively reduce the content of P. Notoginseng parts of the trivalent and pentavalent arsenic, the largest decline of 50%, also can reduce root absorption of arsenic enrichment coefficient. Test adding only pentavalent arsenic, but in all parts of the plant P. Notoginseng trivalent arsenic were detected, indicating that there are a lot of P. Notoginseng body arsenic reduction mechanism. The content of trivalent arsenic stems were higher than pentavalent arsenic, stems are the main places in P. Notoginseng of arsenic reduction mechanism.