Journal Article

PreJuSER-10542

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Control of transpiration by radiation

Pieruschka, R.FZJ* ; Huber, G.FZJ* ; Berry, J. A.

2010
Academy Washington, DC

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Please use a persistent id in citations: doi:10.1073/pnas.0913177107

Abstract: The terrestrial hydrological cycle is strongly influenced by transpiration--water loss through the stomatal pores of leaves. In this report we present studies showing that the energy content of radiation absorbed by the leaf influences stomatal control of transpiration. This observation is at odds with current concepts of how stomata sense and control transpiration, and we suggest an alternative model. Specifically, we argue that the steady-state water potential of the epidermis in the intact leaf is controlled by the difference between the radiation-controlled rate of water vapor production in the leaf interior and the rate of transpiration. Any difference between these two potentially large fluxes is made up by evaporation from (or condensation on) the epidermis, causing its water potential to pivot around this balance point. Previous work established that stomata in isolated epidermal strips respond by opening with increasing (and closing with decreasing) water potential. Thus, stomatal conductance and transpiration rate should increase when there is condensation on (and decrease when there is evaporation from) the epidermis, thus tending to maintain homeostasis of epidermal water potential. We use a model to show that such a mechanism would have control properties similar to those observed with leaves. This hypothesis provides a plausible explanation for the regulation of leaf and canopy transpiration by the radiation load and provides a unique framework for studies of the regulation of stomatal conductance by CO(2) and other factors.

Keyword(s): Carbon Dioxide: metabolism (MeSH) ; Helianthus: metabolism (MeSH) ; Helianthus: physiology (MeSH) ; Light (MeSH) ; Models, Biological (MeSH) ; Nerium: metabolism (MeSH) ; Nerium: physiology (MeSH) ; Photosynthesis: physiology (MeSH) ; Photosynthesis: radiation effects (MeSH) ; Plant Leaves: physiology (MeSH) ; Plant Stomata: metabolism (MeSH) ; Plant Stomata: physiology (MeSH) ; Plant Transpiration: physiology (MeSH) ; Trees: metabolism (MeSH) ; Trees: physiology (MeSH) ; Water: metabolism (MeSH) ; Xanthium: metabolism (MeSH) ; Xanthium: physiology (MeSH) ; Carbon Dioxide ; Water ; J ; plant physiology (auto) ; stomata (auto) ; micrometeorology (auto)

Note: We acknowledge Keith Mott for suggesting the use of near infrared light, Keith Mott, Bernard Genty, and Peter Franks for many discussions that helped us form our ideas, and two reviewers who helped us better express them. We thank Denis Klimov for help with light sources and Larry Giles for technical assistance. R. P. was supported by a Marie Curie fellowship (LIFT 041060) during this work.

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Research Program(s):

1. Terrestrische Umwelt (P24)

Appears in the scientific report 2010

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