Uptake kinetics of different arsenic species in lowland and upland rice colonized with Glomus intraradices

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.