Rahman M Azizur, Hasegawa H, Ueda K, Maki T, Rahman M M
Graduate School of Natural Science and Technology, Kanazawa University, Kakuma, Kanazawa 920-1192, Japan.
Ecotoxicol Environ Saf. 2008 Jun;70(2):311-8. doi: 10.1016/j.ecoenv.2007.07.009. Epub 2007 Nov 9.
The influence of ethylenediaminetetraacetic acid (EDTA) and chemical species on arsenic accumulation in aquatic floating macrophyte Spirodela polyrhiza L. (duckweed) was investigated. The uptake of inorganic arsenic species (arsenate; As(V) and arsenite; As(III)) into the plant tissue and their adsorption on iron plaque of plant surfaces were significantly (p<0.05) higher than those of organic species (monomethylarsonic acid (MMAA) and dimethylarsinic acid (DMAA)). The addition of EDTA to the culture media increased the uptake of As(V) and As(III) into the plant tissue though the MMAA and DMAA uptake were not affected. About 4-6% of the inorganic arsenic species were desorbed or mobilized from iron plaque by EDTA. Desorption of organic arsenic species was not affected by EDTA addition because the co-precipitation occurs only with inorganic species. Phosphate uptake was not affected by EDTA though its concentration in citrate-bicarbonate-EDTA (CBE)-extract was much higher than that of plant tissue. Iron uptake into the plant increased significantly (p>0.05) by EDTA addition to the culture media while its concentration in CBE-extract decreased significantly (p<0.05). The As(inorganic)/Fe ratios in plant were higher than those of CBE-extract which indicate the increased uptake of these arsenic species into the plant relative to the iron. The lower As(organic)/Fe ratios in plant and on CBE-extract suggest the reduction of accumulation of these arsenic species relative to the iron.
研究了乙二胺四乙酸（EDTA）和化学形态对水生漂浮大型植物紫萍（Spirodela polyrhiza L.）中砷积累的影响。植物组织对无机砷形态（砷酸盐；As(V)和亚砷酸盐；As(III)）的吸收及其在植物表面铁膜上的吸附显著（p<0.05）高于有机形态（一甲基胂酸（MMAA）和二甲基胂酸（DMAA））。向培养基中添加EDTA增加了植物组织对As(V)和As(III)的吸收，而MMAA和DMAA的吸收不受影响。约4-6%的无机砷形态被EDTA从铁膜上解吸或活化。添加EDTA对有机砷形态的解吸没有影响，因为共沉淀仅发生在无机形态中。尽管其在柠檬酸-碳酸氢盐-EDTA（CBE）提取物中的浓度远高于植物组织中的浓度，但磷酸盐的吸收不受EDTA影响。向培养基中添加EDTA显著（p>0.05）增加了植物对铁的吸收，而其在CBE提取物中的浓度显著降低（p<0.05）。植物中的As(无机)/Fe比值高于CBE提取物中的比值，这表明相对于铁，这些砷形态在植物中的吸收增加。植物中和CBE提取物上较低的As(有机)/Fe比值表明相对于铁，这些砷形态的积累减少。
