Does transpiration control stomatal responses to water vapour pressure deficit?
Article first published online: 28 JUN 2008
Plant, Cell & Environment
Volume 20, Issue 1, pages 131–135, January 1997
How to Cite
BUNCE, J. A. (1997), Does transpiration control stomatal responses to water vapour pressure deficit?. Plant, Cell & Environment, 20: 131–135. doi: 10.1046/j.1365-3040.1997.d01-3.x
- Issue published online: 28 JUN 2008
- Article first published online: 28 JUN 2008
- Received 4 May 1996; received in revised form 14 June 1996; accepted for publication 23 June 1996
- Abutilon theophrasti;
- Chenopodium album;
- Glycine max;
- stomatal conductance;
- vapour pressure deficit
Three types of observations were used to test the hypothesis that the response of stomatal conductance to a change in vapour pressure deficit is controlled by whole-leaf transpiration rate or by feedback from leaf water potential. Varying the leaf water potential of a measured leaf by controlling the transpiration rate of other leaves on the plant did not affect the response of stomatal conductance to vapour pressure deficit in Glycine max. In three species, stomatal sensitivity to vapour pressure deficit was eliminated when measurements were made at near-zero carbon dioxide concentrations, despite the much higher transpiration rates of leaves at low carbon dioxide. In Abutilon theophrasti, increasing vapour pressure deficit sometimes resulted in both decreased stomatal conductance and a lower transpiration rate even though the response of assimilation rate to the calculated substomatal carbon dioxide concentration indicated that there was no ‘patchy’ stomatal closure at high vapour pressure deficit in this case. These results are not consistent with stomatal closure at high vapour pressure deficit caused by increased whole-leaf transpiration rate or by lower leaf water potential. The lack of response of conductance to vapour pressure deficit in carbon dioxide-free air suggests that abscisic acid may mediate the response.