Aluminium Toxicity and Defence Mechanisms in Plants

Abstract

In recent days, aluminium toxicity is a serious threat to agriculture all over the world. Aluminium (Al) being the most dominant metal in the Earth’s crust exhibits highly toxic effects on the plants grown in acid soils (pH below 5.0). Initially, aluminium toxicity symptoms become apparent in the apical region of the root because of its extreme sensitivity to aluminium. Cell wall rigidification, cell membrane depolarization and cytoskeletal damages are the important primary events that take place under Al stress condition. Adverse impacts of Al on these cellular components cause reduction in cell expansion, decreased nutrient uptake, organeller dysfunctioning and subsequent rapid production of reactive oxygen species (ROS).Transient generation of ROS further induces damage to the nuclear membrane and nucleic acids which ultimately lead to cell apoptosis. In the other hand, mechanisms such as release of organic acids from the root and their binding to Al extracellularly, organic acid mediated intracellular chelation and vacuolar sequestration of Al ions, synthesis of enzymatic and non-enzymatic antioxidants contribute to the Al detoxification process. Understanding the important aspects of Al phytotoxicity and mechanisms of its tolerance would be certainly beneficial to sustain agricultural productivity in acid soils by developing traits with higher resistance against aluminium. So, this article reviews the biochemistry and physiology of Al toxicity along with the various different mechanisms that are used by the plants to detoxify Al. However, emphasis has been given to the mechanisms of Al detoxification. © 2017 by Nova Science Publishers, Inc. All rights reserved.