INFLUENCE OF ECTOMYCORRHIZAL INFECTION ON THE RHIZOSPHERE PH AROUND ROOTS OF MARITIME PINE (PINUS-PINASTER SOLAND IN AIT)

This study examined the influence of mycorrhizal infection on ionic ex changes by roots, by measuring rhizosphere pH and the quantities of pr otons released by roots of mycorrhizal and non-mycorrhizal pine (Pinus pinaster x Suillus collinitus). The effect of inoculation was measure d around individual roots and compared with the effect on the root sys tem as a whole, with root heterogeneity thus being taken into account in structural terms and in terms of functioning. Inoculation enhanced significantly the capacity of roots to release protons in a medium wit h a neutral pH, but the strength of reaction varied with the part of t he root involved. This enhancement could possibly be used to improve t he bioavailability of compounds not readily soluble in particular chem ical conditions of the soil.