Airborne and Soilborne Cues of Herbivory Reduce Damage and Accelerate Flowering For Tomato Plants

Many studies have found that volatile cues from damaged plants can induce resistance to herbivores in undamaged neighbors. However, fewer studies have examined the effects of soilborne cues. Furthermore, there are few studies that have considered the effects of plant-plant communication on plant reproduction. We conducted experiments with tomato seedlings exposing them to airborne and soilborne cues from experimentally damaged neighbors. These plants were then transplanted to the field and the level of damage by chewing and sucking herbivores was observed in the field. We also recorded the time before flowering was initiated by these plants. We found that both airborne and soilborne cues trend to reduce the proportion of leaves that were damaged for plants exposed to cues relative to controls that were near undamaged neighbors. Furthermore, these two cues were found to interact synergistically. Plants that had been exposed to soilborne cues flowered sooner than controls, those exposed to airborne cues, and both cues. These results suggested that soilborne and airborne cues induce different responses in plants.