The Effects of Silicon on Arsenic Accumulation and Speciation in Different Tissues of Mature Rice (Oryza Sativa)

摘要

Rice (Oryza sativa) is one of the staple food crops in the world.Inorganic As and dimethylarsinic acid (DMAⅤ) are predominant As species in rice grain.Arsenite is taken up by rice roots mainly through the Si uptake pathway.To investigate whether Si addition influences As species in mature rice tissues,a soil pot experiment was carried out in a greenhouse.The results showed that Si addition significantly decreased total As concentration in each individual leaf and stem by 2.83-11.7 folds and in husk and grain by 2.8 and 2.9 folds,respectively.AsⅢ,AsⅤ and DMAⅤ were detected in the different tissues of mature rice plants.Inorganic arsenic (the sum of AsⅢ and AsⅤ) was the predominant species,accounting for 54.1％-99.8％ whether Si addition or not.Furthermore,Si addition significantly decreased AsⅢ concentrations and total As levels in different plant tissues compared to-Si treatment (p＜0.001).Further experiments are being conducted to investigate how Si influences arsenic speciation in rice.