Aluminum toxicity and resistance in higher plants

Abstract

Aluminum (Al) is the major element in the soil and exists as a stable complex with oxygen and silicate. When the soil pH is below 5, Al is solubilized in the soil water and absorbed by plant roots. Absorbed Al inhibits root elongation severely within hours. Al toxicity is a very important limitation to worldwide crop production, because 50% of the world’s potentially arable lands are acidic. Thus, many research has been conducted to understand the mechanism of Al toxicity and resistance which is important for stable food production in future. Al resistance can be achieved by mechanisms that facilitate Al exclusion from the root apex and/or by mechanisms that confer the ability of plants to tolerate Al in the plant symplasm. However, despite intense research efforts, there are many aspects of Al toxicity and resistance remain unclear. In this review, Al toxicity and resistance mechanisms are described with the physiological and molecular basis.