The greenhouse experiment was laid out in a factorial combina- tion of three nutrient solutions having different pH and aluminium concentration (pH 6.0, pH 3.5, or pH 3.5 + 1 mM Al), and two mycorrhizal treatments (with AM, +AM or without AM, −AM). Treatments
were organized in a randomized complete-block design with four
replicates. Each plot consisted of six plants. Prior to transplan- ting, half of the pots received a commercial mycorrhizal inoculum carrying Rhizophagus irregularis (formerly Glomus intraradices) and Funneliformis mosseae (formerly Glomus mosseae) (Aegis Micro- granule, Italpollina S.p.A., Rivoli Veronese, Italy) by mixing 15 L of inoculum containing bulking material composed of 95% minerals as
granular carriers, plus root fragments and spores (25 spores mL−1 of
R. irregularis and 25 spores mL−1 of F. mosseae) per m3 of substrate.