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.