Respiratory alternative oxidase responds to both low- and high-temperature stress in Quercus rubra leaves along an urban–rural gradient in New York
Article first published online: 6 JUN 2011
© 2011 The Authors. Functional Ecology © 2011 British Ecological Society
Volume 25, Issue 5, pages 1007–1017, October 2011
How to Cite
Searle, S. Y., Bitterman, D. S., Thomas, S., Griffin, K. L., Atkin, O. K. and Turnbull, M. H. (2011), Respiratory alternative oxidase responds to both low- and high-temperature stress in Quercus rubra leaves along an urban–rural gradient in New York. Functional Ecology, 25: 1007–1017. doi: 10.1111/j.1365-2435.2011.01875.x
- Issue published online: 22 SEP 2011
- Article first published online: 6 JUN 2011
- Received 5 January 2011; accepted 9 May 2011 Handling Editor: Mark Tjoelker
- cytochrome oxidase;
- leaf respiration;
- nonstructural carbohydrates;
- oxygen isotope discrimination;
- seasonal variation;
- urban ecology
1. Urban–rural transects can be utilized as natural gradients of temperature and also as a tool to predict how plant ecology and physiology might respond to expected global change variables such as elevated temperatures, CO2 and inorganic nitrogen deposition.
2. We investigated differences in respiration (R) and the balance of electron partitioning through the cytochrome (CP) and alternative (AP) pathways in leaves of mature Quercus rubra L. trees along a transect from New York City to the Catskill Mountains over the course of one growing season. In addition, we investigated the effects of elevated temperature on Q. rubra seedlings in a controlled environment study.
3. In the field study, we found that urban-grown leaves often respired at greater rates than leaves grown at other sites and that this was likely due to higher leaf nitrogen. At each site, R at the prevailing growth temperature declined steadily throughout the growing season despite higher temperatures at the end of the summer. Differences in R were associated with changes in the relative abundances of cytochrome and alternative oxidase proteins. Oxygen isotope discrimination (D), which reflects relative changes in AP and CP partitioning, was negatively correlated with daily minimum temperature in trees grown at the colder rural sites, but not at the warmer urban sites.
4. In the growth cabinet study, we found that R acclimated to elevated temperatures and that this was accompanied by a steady increase in D.
5. These findings that AP partitioning increases with both high and low temperatures show that the AP may play an important role in plant responses to environmental conditions that elicit stress, and not simply to specific conditions such as low temperature.