Aluminum toxicity in plant cell

Aluminium being the third most abundant metal in the earth's crust is in its toxic form a serious threat for crop productivity in acid soils, which comprise almost half of the arable land. As the most phytotoxic form is considered free ion Al3+ , which affects root growth by acting in the root apical zone, resulting in growth inhibition in a very short time at micromolar concentrations. At cellular and molecular level, many cell components are affected by aluminium toxicity including cell wall, plasma membrane, signal transduction pathways, calcium homeostasis, DNA and numerous cytoplasmic enzymes. Although it is difficult to distinguish the primary targets from the secondary effects so far, understanding of the target sites of aluminium toxicity is helpful to elucidate the mechanisms by which aluminium exerts its deleterious effects in root growth. On the other hand, some plant species have evolved mechanisms to cope with aluminium toxicity. In the future, the attention should be paid to basic mechanisms of aluminium toxicity and our understanding of the current problem should be unified. Key words: Al toxicity, Al resistance/tolerance, phytotoxicity, Al stress, acid soils, root elongatio