Our two hosts responded differently to AM fungi: a highly
dependent plant showed both strong positive and negative
response to AM fungal inoculation depending on the soil nutrient
status. Conversely, a plant with less mycorrhizal dependence
showed little nutrient response, positive or negative. In terms
of specific isolates, only G. intraradices consistently ameliorated
nutrient levels in plants, considering all nutrients and plant combinations.
This study shows that when looking for patterns in AM
fungal/plant nutrition, fertilization regime (and consequently soil
nutrient status) is an important factor in predicting the outcome. If
future studies aim to clarify the multifunctional nature of the AM
symbiosis, it is essential to consider the context of the environment.