Abstract: Arsenic pollution seriously threatens human health and environment safety, being a very prominent environmental issue to be urgently solved in the world. In natural environment and soil systems, arsenic exists in complicated forms, but the plant arsenic poisoning is mainly from As(V) and As(Ⅲ) exposure. As(V) can be absorbed by plant roots through Pi channel, and reduced rapidly to As(Ⅲ) by arsenate reductase. As(Ⅲ) can be transported into plants through NIP channel, and subsequently either transformed into methylated arsenic by arsenic methyltransferase or chelated with the thiol of GSH and PCs. These arsenic compounds can be sequestrated in root cell vacuoles or transported to plant aerial parts. Meanwhile, a part of absorbed arsenic can be discharged to external media. All of these can help to detoxify the arsenic in plants. This paper reviewed the latest research progress on the arsenic- resistance of crops, especially rice, with the focus on the mechanisms of As(V) and As(Ⅲ) absorption and excretion, As(V) reduction, and As(Ⅲ) methylation and chelation. The major topics of future research on arsenic toxicity were proposed.

Key words: inorganic arsenic, absorption, metabolism, transportation, plant