Variation in carbon availability, defense chemistry and susceptibility to fungal invasion along the stems of mature trees
Article first published online: 16 NOV 2012
© 2012 The Authors. New Phytologist © 2012 New Phytologist Trust
Volume 197, Issue 2, pages 586–594, January 2013
How to Cite
Goodsman, D. W., Lusebrink, I., Landhäusser, S. M., Erbilgin, N. and Lieffers, V. J. (2013), Variation in carbon availability, defense chemistry and susceptibility to fungal invasion along the stems of mature trees. New Phytologist, 197: 586–594. doi: 10.1111/nph.12019
- Issue published online: 18 DEC 2012
- Article first published online: 16 NOV 2012
- Manuscript Accepted: 28 SEP 2012
- Manuscript Received: 10 JUL 2012
- Natural Sciences and Engineering Research Council of Canada (NSERC)
- Alberta Sustainable Resource Development
- West Fraser
- the University of Alberta
- Eckehart Marenholtz, Iain Grant-Weaver
- Lucas Veldhoen
- Pak Chow
- If carbon (C) sinks withdraw carbohydrates as they are transported along tree stems, carbohydrate availability may depend on local sink strength and distance from sources. Defenses, including monoterpenes – a major component of resin – limit the invasibility of pines. Since carbohydrate reserves fund monoterpene synthesis, we hypothesized that monoterpene concentrations in pine stems would decrease from the crown to the lower stem, and susceptibility to fungal infection would increase.
- Here, we measured carbohydrate and monoterpene concentrations along the stems of lodgepole pine trees (Pinus contorta var. latifolia) before inoculating with a blue-stain fungus at different heights. After 6 wk, we assessed tree responses to fungal infection based on lesion length and carbohydrate mobilization.
- Concentrations of carbohydrates and monoterpenes in the phloem before inoculation decreased with distance from the crown, whereas lesion lengths after inoculation increased. However, trees mobilized sugars in response to fungal infection such that carbohydrate reserves near lesions were similar at all heights.
- Despite C mobilization, the lower stem was more vulnerable than the upper stem. Consistent with predictions based on sink–source relationships, vulnerability occurred where carbohydrates were less available, and likely resulted from C withdrawal by sinks higher in the supply chain.