Woody clockworks: circadian regulation of night-time water use in Eucalyptus globulus
Article first published online: 25 JUN 2013
© 2013 The Authors. New Phytologist © 2013 New Phytologist Trust
Volume 200, Issue 3, pages 743–752, November 2013
How to Cite
Resco de Dios, V., Díaz-Sierra, R., Goulden, M. L., Barton, C. V. M., Boer, M. M., Gessler, A., Ferrio, J. P., Pfautsch, S. and Tissue, D. T. (2013), Woody clockworks: circadian regulation of night-time water use in Eucalyptus globulus. New Phytologist, 200: 743–752. doi: 10.1111/nph.12382
- Issue published online: 11 OCT 2013
- Article first published online: 25 JUN 2013
- Manuscript Accepted: 27 MAY 2013
- Manuscript Received: 14 MAR 2013
- Australian Government Department of Agriculture, Fisheries and Forestry
- Ramón y Cajal program. Grant Number: RYC-2008-02050
- circadian clock;
- night-time stomatal conductance;
- sap flux;
- water balance
- The role of the circadian clock in controlling the metabolism of entire trees has seldom been considered. We tested whether the clock influences nocturnal whole-tree water use.
- Whole-tree chambers allowed the control of environmental variables (temperature, relative humidity). Night-time stomatal conductance (gs) and sap flow (Q) were monitored in 6- to 8-m-tall Eucalyptus globulus trees during nights when environmental variables were kept constant, and also when conditions varied with time. Artificial neural networks were used to quantify the relative importance of circadian regulation of gs and Q.
- Under a constant environment, gs and Q declined from 0 to 6 h after dusk, but increased from 6 to 12 h after dusk. While the initial decline could be attributed to multiple processes, the subsequent increase is most consistent with circadian regulation of gs and Q.
- We conclude that endogenous regulation of gs is an important driver of night-time Q under natural environmental variability. The proportion of nocturnal Q variation associated with circadian regulation (23–56%) was comparable to that attributed to vapor pressure deficit variation (25–58%). This study contributes to our understanding of the linkages between molecular and cellular processes related to circadian regulation, and whole-tree processes related to ecosystem gas exchange in the field.