The effect of Glomus intraradices on four As species (arsenate; arsenite; dimethylarsinic acid, DMA; and monomethylarsonic acid. MMA) uptake by lowland rice and upland rice were investigated based on two experiments: (1) high (0-0.05 mM) and low (0-2.5 mM) - affinity uptake kinetics of four As species in the short-term, and (2) As speciation in rice treated with 1 mM arsenate, arsenite, DMA or MMA solutions. The results showed that mycorrhizal roots of two rice cultivars reduced the arsenate uptake significantly (P < 0.001) in low-affinity uptake system, and decreased the uptake of arsenite and MMA noticeably (P < 0.05) in high or low-affinity uptake systems. The four As species influx have significant differences (P < 0.05) between two rice varieties in low-affinity uptake systems. In the arsenate treatment, the ratio of arsenate/arsenite reduced in shoots while increased in roots because of G. intraradices presence. (C) 2011 Elsevier B.V. All rights reserved.