DAMAGE-INDUCED RESISTANCE IN SAGEBRUSH: VOLATILES ARE KEY TO INTRA- AND INTERPLANT COMMUNICATION
- 1 April 2006
- Vol. 87 (4), 922-930
- https://doi.org/10.1890/0012-9658(2006)87[922:drisva]2.0.co;2
Abstract
Airborne communication between individuals, called "eavesdropping" in this paper, can cause plants to become more resistant to herbivores when a neighbor has been experimentally clipped. The ecological relevance of this result has been in question, since individuals may be too far apart for this interaction to affect many plants in natural populations. We investigated induced resistance to herbivory in sagebrush, Artemisia tridentata, caused by experimental clipping of the focal plant and its neighbors. We found no evidence for systemic induced resistance when one branch was clipped and another branch on the same plant was assayed for naturally occurring damage. In this experiment, air contact and plant age were not controlled. Previous work indicated that sagebrush received less damage when a neighboring upwind plant within 15 cm had been experimentally clipped. Here we found that pairs of sagebrush plants that were up to 60 cm apart were influenced by experimental clipping of a neighbor. Furthermore, we observed that most individuals had conspecific neighbors that were much closer than 60 cm. Air contact was essential for communication; treatments that reduced airflow between neighboring individuals, either because of wind direction or bagging, prevented induced resistance. Airflow was also necessary for systemic induced resistance among branches within an individual. Reports from the literature indicated that sagebrush is highly sectorial, as are many desert shrubs. Branches within a sagebrush plant do not freely exchange material via vascular connections and apparently cannot rely on an internal signaling pathway for coordinating induction of resistance to herbivores. Instead, they may use external, volatile cues. This hypothesis provides a proximal explanation for why sagebrush does not demonstrate systemic induced resistance without directed airflow, and why airborne communication between branches induces resistance.Keywords
This publication has 36 references indexed in Scilit:
- Knowing when to draw the line: designing more informative ecological experimentsFrontiers in Ecology and the Environment, 2005
- Chemical information transfer between plants:Biochemical Systematics and Ecology, 2001
- Signals Regulating Multiple Responses to Wounding and HerbivoresCritical Reviews in Plant Sciences, 2001
- Defoliation of alders (Alnus glutinosa) affects herbivory by leaf beetles on undamaged neighboursOecologia, 2000
- Herbivory-induced volatiles elicit defence genes in lima bean leavesNature, 2000
- Assimilate movement dictates remote sites of wound-induced gene expression in poplar leaves.Proceedings of the National Academy of Sciences, 1991
- Interplant communication: airborne methyl jasmonate induces synthesis of proteinase inhibitors in plant leaves.Proceedings of the National Academy of Sciences, 1990
- Mechanism of damage-induced alkaloid production in wild tobaccoJournal of Chemical Ecology, 1989
- Long-term inducible resistance in birch foliage: triggering cues and efficacy on a defoliatorOecologia, 1985
- Physiological Responses of Big Sagebrush to Different Types of Herbage RemovalJournal of Range Management, 1960