2007 年 13 巻 1 号 p. 15-19
Some plants that accumulate the arsenic compounds have attracted attention as hyperaccumulators, and contribute to metal-extraction technique for the clean-up of contaminated environments. This study investigated the effects of arsenic species and bacterial activities on the arsenic uptakes of the hyperaccumulator fern Pteris vittata. The microbial activities in the lake water mineralized DMAA to inorganic arsenic, and some bacterial isolates degraded DMAA. When P. vittata was cultivated in the hydroponic culture medium, the plant accumulated inorganic arsenic to about 1700 As-mg/kg, while it hardly accumulated dimethylarsinic acid (DMAA) showing lower accumulation of below 50 As-mg/kg. The DMAA-mineralizing bacteria and the lake water sample, which were added into P. vittata culture medium, increased until 20 fold the plant arsenic accumulations. Furthermore, the bacterial addition also induced the arsenic accumulation of P. vittata, which were cultivated in the sterilized normal soils spiked with DMAA or the arsenic contaminated soils. Presumably, the bacterial mineralization supported the plant accumulate DMAA via inorganic arsenic.
