INVOLVEMENT OF MULTIPLE ALUMINUM EXCLUSION MECHANISMS IN ALUMINUM TOLERANCE IN WHEAT

The goal of this study was to determine if AI-chelators other than mal ate are released from root apices and are involved in Al-tolerance in different wheat (Triticum aestivum L.) genotypes. Also we wanted to es tablish if root exudates contribute to increases in rhizosphere pH aro und the root tip. In seedlings of Al-tolerant Atlas, we have documente d a constitutive phosphate exudation from the root apex. Because phosp hate can complex Al and bind protons, it could play an important role in Al tolerance, both via complexation of Al3+ and by contributing to the alkalinization of rhizosphere pH observed at the apex of Atlas. Th is study suggests that in wheat, Al-tolerance can be mediated by multi ple exclusion mechanisms controlled by different genes.