Effect of arbuscular mycorrhizal colonisation on the growth and phosphorus nutrition of Populus euramericana c.v. Ghoy

Arbuscular mycorrhizal (AM) fungi are known to associate with a range of Populus species particularly in the early stages of development yet there is little information on their potential role in sustainable biomass production. Moreover, while the AM association may enhance plant establishment, growth and nutrition, different AM fungi (AMF) vary in their ability to confer such benefits. In this study we investigated the impact of four different AMF on growth and phosphorus nutrition of Populus euramericana c.v. Ghoy. Plant biomass, particularly root biomass, was generally reduced by AMF colonisation and the extent of this reduction varied with the AMF species that had colonised the roots. This growth reduction was not simply due to differences in root colonisation, which ranged from 59 to 71% by the end of the experiment at 105 d and did not vary among the AMF screened. Phosphorus content was also lower in some AMF treatments than in non-AMF controls after growth for 105 d although P concentration in aboveground tissues (stems and leaves) was higher. The possible interaction between AMF and poplar in converted arable systems is discussed.