http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
( Chien Hui Syu ),( Pei Yu Jiang ),( Hsuan Han Huang ),( Wen Ting Chen ),( Tzu Huei Lin ),( Dar Yuan Lee ) 한국환경농학회 2012 한국환경농학회 워크샵자료 Vol.2012 No.2
The iron plaque formed on rice root has been confirmed to be a barrier on the uptake of arsenic in many hydroponic experiments. However, few studies provide the information about the relationship between soil characteristics, iron plaque formation and As uptake by rice in Ascontaminated soils. Therefore, the aim of this study is to investigate the effect of the rice root`s iron plaques on the As uptake by rice plants grown in geologically As-contaminated soils with high contents of iron oxides and organic matter from the Guandu Plain of northern Taiwan. A soil flooding incubation study was performed and a pot experiment was conducted. The rice seedling was pre-cultivated in solution cultures and then transplanted in three level As-contaminated soils for growing 39 days. The amounts of iron plaque on rice root were determined by extraction using dithionite-citrate-bicarbonate (DCB). The As species on iron plaque and the concentrations of As and Fe in iron plaque, root, root base and shoot of rice plants were determined. The results of the soil incubation study showed that both As and Fe concentrations in the soil solutions increased with flooding time due to reductive dissolution of iron oxides induced by high contents of organic matter in soils. High amounts of iron plaque were deposited on rice roots and large amounts of As were sequestrated in these iron plaques. Results of the As K-edge X-ray absorption nearedge spectroscopy (XANES) indicated that arsenate was the main species of arsenic sorbed on iron plaque of rice roots. About 74.0 to 93.2 % of total As released from soils were distributed in the iron plaques and only small proportion was distributed in the rice plants. This study provides evidence that the iron plaques of the rice roots was the main controlling factor in limiting the uptake and accumulation of As into the rice plants grown in paddy soils with high contents of iron oxides and organic matter, meanwhile, it suggests that enhancement of iron plaque formation could be the approach used for reducing the uptake of As by paddy rice grown in As-contaminated soils.