Effects of arbuscular mycorrhizal fungi on plant secondary chemistry and pollination

Above – belowground multi-species interactions can be mediated by plant secondary chemistry. To investigate selection on secondary compounds in these above- and belowground interactions, we are using two Californian vernal pool mesamint species of the genus Pogogyne. Few studies have shown that soil biota - plant interactions can affect pollination. Here, we tested 1) whether plants respond to arbuscular mycorrhizal fungi (AMF), 2) whether they have different volatile terpenoid chemotypes 3) whether AMF affect terpenoid composition and concentration. 4) whether AMF and terpenoids affect pollination. We found genetic variation in plant growth response to AMF (Glomus sp.). Some, but not all populations had increased growth with AMF. AMF had no effect on volatile terpenoid composition but there was a trend that terpenoid concentrations were higher in plants growing without AMF. Plants growing with AMF had more flowers and larger flowers compared to plants growing without AMF, indicating that AMF could potentially affect pollination. Currently, we are testing how AMF and terpenoids are affecting pollination and plant fitness in the field.