Departmento de Ecología, Facultad de Agronomía, Universidad de Buenos Aires, 1417 Buenos Aires, Argentina.
Do stomata respond to relative humidity?
Article first published online: 28 APR 2006
Plant, Cell & Environment
Volume 14, Issue 1, pages 127–132, January 1991
How to Cite
APHALO, P. J. and JARVIS, P. G. (1991), Do stomata respond to relative humidity?. Plant, Cell & Environment, 14: 127–132. doi: 10.1111/j.1365-3040.1991.tb01379.x
- Issue published online: 28 APR 2006
- Article first published online: 28 APR 2006
- Received 6 April 1990; received in revised form 17 July 1990; accepted for publication 9 August 1990
- Hedera helix;
- gas exchange;
- stomatal conductance;
- relative humidity;
- water vapour saturation deficit;
- leaf temperature.
Abstract. The objective of the work reported was to answer the following questions: (1) Do stomata respond to both humidity and temperature? (2) Do these responses interact in such a way that relative humidity at the leaf surface is a more appropriate variable than water vapour saturation deficit at the leaf surface and yields a simpler description of the compound response? To answer these questions, we measured the response of leaf conductance to humidity under constant leaf temperature, and the response to increasing leaf temperature under constant relative humidity and under constant water vapour saturation deficit. We found that, in Hedera helix subsp. canariensis (Willd.) Coutinho, there was a reversible response to humidity under constant temperature, and that there was also a response to temperature under constant relative humidity. The relationship between leaf conductance and relative humidity was different when measured at the same temperature rather than at different temperatures. An inversely proportional response was consistently obtained when stomatal conductance was expressed in relation to water vapour saturation deficit. The interaction between the effects of leaf temperature and water vapour saturation deficit was not compatible with a mechanism of response to humidity and temperature based solely on relative humidity. From these data, we conclude that water vapour saturation deficit is a more appropriate variable for describing stomatal responses to humidity.