Submitted to: Book Chapter
Publication Type: Book / chapter
Publication Acceptance Date: 1/29/1997
Publication Date: N/A
Citation: Interpretive Summary: Not required.
Technical Abstract: Aluminum phytotoxicity is a major factor limiting crop productivity on acid soils which comprise approximately 30% of the world s land area. A large proportion of the acid soils occur in developing countries in the tropics and subtropics; thus Al toxicity limits the growth of crops in those countries where food production is very critical. Hence, it is clear that Al phytotoxicity is a major agricultural problem throughout the world. In recent years, the growing awareness of the agronomic importance of this problem has resulted in a dramatic increase in basic research aimed at increasing our understanding of the cellular mechanisms of both Al phytotoxicity, and genetic-based mechanisms of Al resistance. Despite this increase in research into fundamental aspects of Al toxicity and resistance, this research topic is still poorly understood, and contains a number of controversies. In this chapter, we address the recent research into the underlying mechanisms of aluminum phytoxicity and the processes plants employ to resist toxicity. The review of Al toxicity will consider the potential site(s) of Al toxicity within the plant root, and how Al might interact with each of these sites. Processes involved in Al entry across the plasma membrane will be discussed, as well as possible symplasmic sites of toxicity involving signal transduction processes and the cytoskeleton. In terms of aluminum resistance, most of the focus will be on the recent identification and characterization of an Al resistance mechanism based on Al-induced release of Al chelating compounds from the root, which result in exclusion of Al from the root apex.