Pattern of root colonization by arbuscular mycorrhizal fungi in Verbesina virgata and their effects on plant growth and leaf physical attributes

Abstract

Verbesina virgata (Asteraceae) is the stable food of generalist herbivores in xerophytic vegetation of southern Mexico City where nitrogen and phosphorous are limiting soil resources for plant growth and therefore it is likely that arbuscular mycorrhizal fungi play an important role in the biology of V. virgata. We characterized root colonization by arbuscular mycorrhizal fungi of V. virgata under field conditions and explored the effects of arbuscular mycorrhizal fungi on plant attributes in a nursery experiment. Root colonization of V. virgata under field conditions varied seasonally. Our experimental data suggest that mycorrhizal interaction is costly for V. virgata. Arbuscular mycorrhizal interaction increased the photosynthetic capabilities of V. virgata but plants grown with arbuscular mycorrhizal fungi were smaller than control plants. In addition, plants colonized by arbuscular mycorrhizalM fungi had larger but thinner leaves than control ones, suggesting that the former may be more acceptable for herbivores.