Reduced leaf expansion as a cost of systemic induced resistance to herbivory
Article first published online: 28 FEB 2003
Volume 17, Issue 1, pages 75–81, February 2003
How to Cite
Moore, J. P., Taylor, J. E., Paul, N. D. and Whittaker, J. B. (2003), Reduced leaf expansion as a cost of systemic induced resistance to herbivory. Functional Ecology, 17: 75–81. doi: 10.1046/j.1365-2435.2003.00708.x
- Issue published online: 28 FEB 2003
- Article first published online: 28 FEB 2003
- Received 27 July 2002; revised 14 October 2002; accepted 18 October 2002
- Gastrophysa viridula;
- induced resistance;
- Rumex obtusifolius
- 1We investigated whether increases in cell wall peroxidases link the benefits of induced resistance and the potential ecological costs of reduced leaf expansion.
- 2Rumex obtusifolius is a host plant of the chrysomelid beetle Gastrophysa viridula. The effect of feeding by G. viridula on plant physiology and activity of cell wall-bound peroxidase activity in the plant was measured under controlled conditions.
- 3Gastrophysa viridula were applied to fully expanded leaf 4, and expansion of leaf 8 was measured over 22 days. Removal of leaf tissue by the herbivore delayed subsequent leaf emergence in treated plants and temporarily reduced the expansion rate of leaf 8, beginning 5 days after treatment. This reduction continued for 4 days when compared with non-treated plants, and reduced final leaf area by approximately 37%.
- 4Final epidermal cell areas in leaf 8 were reduced by approximately 13%, while epidermal cell numbers remained unchanged.
- 5Cell wall-bound peroxidase activity was measured in leaf 8 over a 7-day period following attack. Activity increased within 24 h following the start of treatment and peaked at day 3.
- 6We postulate a herbivore-induced systemic mechanism linking reductions in cell expansion and subsequent leaf growth rates as a result of an increase in cell wall-bound peroxidase activity.
- 7Herbivore grazing commonly reduces subsequent host growth, and the assumption has been that this is largely due to the consequences of leaf area lost to grazing. This study suggests that reduced growth, and the associated ecological costs result from induced resistance, and are the consequence of a more subtle direct physiological effect in constraining leaf expansion.