ibclogo XVI International Botanical Congess


Abstract Number: 5156
Session = 11.10.2


ALUMINIUM TOXICITY AND TOLERANCE IN PLANTS


Z. Rengel, University of Western Australia, Perth, Australia


Plants evolved different mechanisms of Al resistance at various levels of plant organisation (metabolic, physiological, structural or developmental). Measurement of Al uptake by complex plant tissues is complicated by a huge reservoir of bound Al in the cell wall and a slow rate of uptake across the plasma membrane. Differences in the electrical and chemical properties of the cell wall, as well as the plasma membrane surface, may influence selective uptake and differential resistance to Al. Early toxicity of Al coincides with an increased activity of cytosolic Ca ions. Exudation of Al-chelating substances, e.g. phosphate, malate or citrate, into the rhizosphere occurs as early as 15 min after exposure to Al and results in complexing of Al into non-toxic forms. An increased exudation of malate correlates well with Al resistance in a segregating population of seedlings.


HTML-Version made 7. July 1999 by Kurt Stüber