[Effects of arsenic from soil and irrigation-water on As accumulation on the root surfaces and in mature rice plants (Oryza sativa L.)].

A compartmented soil-glass bead culture system was used to investigate characteristics of arsenic accumulation in iron plaque and in mature rice plants irrigated using water with arsenic in greenhouse. Arsenic was supplied as a solution of Na3AsO4 * 12H2O at the following stages: tillering, stem elongation, booting, flowering and grain filling. The whole plant was separated into four parts and As concentrations were analyzed in DCB (dithionite-citrate-bicarbonate)-extraction, root, straw, rice husk and grain respectively. The results show that irrigation-water with arsenic has no significant effect on biomass of straw and grain. Arsenic concentrations are distributed in different components of mature rice with the ranking of iron plaque > root > straw > husk > grain. Arsenic in straw and grain just derive from soil in control, and derive from soil and irrigation-water in arsenic treatment. About 76.5% and 71.0% of total arsenic in rice straw are from soil for lines of YY-1 and 94D-64 respectively. There is no significant difference between two lines. However, about 33.6% of total arsenic in grain of YY-1 comes from irrigation-water with arsenic, and only 15.2% of total arsenic in grain of 94D1-64 is from irrigation-water with arsenic. There is a significant difference between YY-1 and 94D-64. Arsenic concentrations in rice grain are lower than the food safety limitation in China (0.7 mg x kg(-1)).