• 关键词：三价砷  五价砷  一甲基砷  二甲基砷  盆栽实验

• 基金项目：国家“十一五”计划科技支撑项目(No.2006BAJ05A08);国家重点基础研究发展计划(973)(No.2008CB418201)

• 王玲梅
• 1. 中国科学院地理科学与资源研究所, 北京 100101; 2. 中国科学院研究生院, 北京 100049

• 韦朝阳
• 中国科学院地理科学与资源研究所, 北京 100101

• 杨林生
• 中国科学院地理科学与资源研究所, 北京 100101

• 段桂兰
• 中国科学院生态环境研究中心, 北京 100085

• 摘要：以2个水稻品种威优402号和Ⅱ优416号为实验材料,采用温室栽培方法研究对比两个品种水稻在人工添加砷处理(0、10、20和40mg·kg^-1)和模拟自然砷污染(贵州高砷土和北京褐土的混合土,质量比为1:1)胁迫条件下的生长发育状况,分析砷在水稻不同部位的累积、形态转化及其健康风险.砷处理显著地抑制了两个品种水稻的生长,水稻地上与地下部生物量、株高和穗数随砷处理水平的提高均出现明显的下降,但Ⅱ优416号的下降幅度明显低于威优402号.两个品种水稻籽粒中砷含量随砷处理水平提高也显著升高,人工添加砷各处理条件下,两个品种水稻稻谷中砷含量没有显著性差异;而在模拟自然砷污染土中,Ⅱ优416号稻谷中砷含量平均值为0.062mg·kg^-1,明显低于威优402号稻谷平均值的0.278mg·kg^-1.两个品种水稻各部位砷的转运系数在低砷处理时(10mg·kg^-1)出现显著的升高,而在其他处理条件下保持不变.无论何种水稻品种,水稻各部位砷形态的组成和比例无显著性差异,水稻根、茎、叶中主要为无机砷,稻谷中无机和有机砷各占60%和40%.依据WHO相关建议标准,种植水稻品种Ⅱ优416号的健康风险要明显低于种植威优402号.

• Abstract：Arsenic is toxic and carcinogenic,so consumption of arsenic accumulated rice may produce serious health risks. Rice varieties (Oryza sativa L.) that accumulate the least arsenic,especially in the rice grain,are desired. Two rice varieties,named Weiyou 402(WY) and Eryou 416(EY) were selected to grow in arsenic spiked soils (0,10,20 and 40 mg·kg^-1 arsenic) and "natural" arsenic soils (1:1 of geogenic high level arsenic soil from Guizhou province and silt loam soil from Beijing) in a greenhouse,to compare their arsenic uptake,accumulation,speciation and related health risks. Arsenic was found to greatly inhibit the growth of the two rice varieties,including the biomass of shoots and roots,plant height and the number of spikes,however,EY was less affected than WYby the arsenic treatments. Arsenic in rice grain increased with the addition of arsenic in soils,both in WYand EY,with no difference between the two varieties; however,in natural arsenic soils,EY accumulated significantly less arsenic in rice grain than that of WY,with average arsenic contents measured as 0.062 and 0.278 mg·kg^-1 for EYand WY,respectively. Under low arsenic treatment (10 mg·kg^-1),more arsenic was translocated from roots to stalks and leaves,whereas no changes were found for these in other arsenic treatments. The constitution and proportion of arsenic species in different parts of the two rice varieties were similar,only non-organic arsenate and arsenite were found in roots,stalks and leaves,while in the rice grains organic arsenic,including MMA and DMA,occupied 40% of the total arsenic. We suggest planting EYrice instead of WYin mining areas in order to reduce the health risks of arsenic.

• Key words：arsenate  arsenite  MMA  DMA  pot trials

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