作　　者： ; ; ; ; ;

机构地区： 昆明理工大学环境科学与工程学院

出　　处： 《生态学报》 2012年第16期5002-5013,共12页

摘　　要： 采用室内溶液培养法,运用气相色谱-质谱联用(Gas chromatography-mass spectrometry,GC-MS)技术测定在As(Ⅲ)、As(Ⅴ)和二甲基胂酸(Dimethylarsinic acid,DMA)3种形态砷(浓度0—5.0 mg/L)胁迫下,砷超富集植物黑藻(Hydrilla verticillata(Linn.f.)Royle.)和非砷超富集植物竹叶眼子菜(Potamogeton malaianus Miq.)体内生成和体外分泌的7种有机酸的含量。结果表明,黑藻体内草酸、丙二酸、柠檬酸、苹果酸和棕榈酸都显著高于竹叶眼子菜(P<0.05)。在As(Ⅲ)处理时,黑藻体内柠檬酸、苹果酸、棕榈酸、亚麻酸和总有机酸显著下降,竹叶眼子菜棕榈酸显著下降;在As(Ⅴ)处理时,黑藻棕榈酸和总有机酸显著下降,竹叶眼子菜棕榈酸显著下降;在DMA处理时,黑藻草酸、柠檬酸和苹果酸显著下降,竹叶眼子菜棕榈酸、亚麻酸和总有机酸显著下降。黑藻在As(Ⅲ)处理下棕榈酸、亚麻酸、总有机酸和As(Ⅴ)处理下草酸含量与体内As含量呈显著负相关(P<0.05),而竹叶眼子菜在As(Ⅲ)或DMA处理下棕榈酸、亚麻酸、总有机酸含量以及在DMA处理下柠檬酸含量与体内As含量均呈显著负相关(P<0.05)。两种植物根系分泌物中均检测出草酸、丙二酸、琥珀酸和棕榈酸,但只有在As(Ⅲ)或As(Ⅴ)处理时黑藻分泌的草酸与体内As含量呈显著正相关。本研究表明As(Ⅲ)或As(Ⅴ)胁迫下黑藻向体外分泌草酸是其超富集砷的一种重要机制。 Organic acids widely exist in plants and environment.They can chelate metals and participate in the metabolitic process of metal uptake,translocation and accumulation,and thus play an important role in plant metal tolerance and detoxification.The changes of organic acid contents in terrestrial plants under arsenic stress have been well documented,but little information is available regarding the changes of organic acids in aquatic plants under different arsenic speciation treatments.The arsenic uptake abilities varied among the aquatic plants.The comparsion between plant species regarding their arsenic-accumulating abilities could provide valuable information in understanding arsenic uptake mechanism.The results of a previous study showed that Hydrilla verticillata can hyperaccumulate arsenic with an average concentration of 282 mg/kg in plants from water containing 0.046 mg/L As.However,the concentrations of arsenic in Potamogeton malaianus were only 129 and 121 mg/kg when exposed to 5.0 mg/L As（Ⅲ） or As（Ⅴ）,respectively. In the present research,a hydroponic culture method,together with gas chromatography-mass spectrometry（GC-MS）,was used to evaluate the organic acid contents in plants and root exudation of Hydrilla verticillata（arsenic hyperaccumulator） and Potamogeton malaianus（non-hyperaccumulator） as affected by arsenic of different species [As（Ⅲ）,As（Ⅴ）,dimethylarsinate（DMA）].Arsenic concentrations were applied in the range of 0—5.0 mg/L.The results showed that the natural contents of oxalic,malonic,citric,malic and palmitic acids in H.verticillata were significantly higher than those of P.malaianus（P〈0.05）.In As（Ⅲ） treatments,the contents of citric,malic,palmitic,linolenic and total organic acids significantly decreased in H.verticillata,and the similar decreasing trend was also observed for palmitic acid content in P.malaianus.In the As（Ⅴ） treatments,a significant decrease was observed for the contents of palmitic acid and total organic acids in H.

关 键 词： 砷 有机酸 根分泌物 黑藻 竹叶眼子菜

领　　域： [环境科学与工程]