Mineral acquisition by mycorrhizal maize grown on acid and alkaline soil

Arbuscular mycorrhizal (AM) fungi can enhance plant acquisition of mineral nutrients and function over relatively broad pH ranges. We have determined the effect of the AM fungi Glomus etunicatum WV579A (Ge), G. diaphanum WV579B (Gd), and G. intraradices WV894 (Gi) on the acquisition of minerals by maize (Zea mays L.) grown on acid (pH 4.2 and 4.6) and alkaline (pH 7.8 and 8.0) soils in a greenhouse. Shoot concentrations of P, Ca, Mg, K, Cu and Si were lower and Mn, Fe and Zn were higher while the total shoot contents of N, P, S, Ca, Mg, K, Na, Cu, B and Si were lower and Mn, Fe and Zn were higher in plants grown on acid compared to alkaline soil. With few exceptions, mycorrhizal (AM) plants had higher mineral concentrations and contents than non-mycorrhizal (nonAM) plants. The three AM isolates were generally comparable for enhancing acquisition of minerals in plants grown on acid soil, while Gi and Ge plants absorbed more minerals than Gd plants grown on alkaline soil. Many of the enhanced mineral acquisition effects were greater than could be accounted for by increases in shoot biomass. Reduced acquisition of P by Ge and Al by Gi plants grown on acid soil were noted. These results provide evidence that Glomus isolates effectively enhance mineral acquisition over wide ranges of soil pH (∼3.5 pH units), and that AM isolates varied extensively in enhancing or reducing mineral acquisition in maize.