Effect of light quality on stomatal opening

Effect of light quality on stomatal opening in leaves of Xanthium strumarium L.

by Sharkey T. D., Raschke K. (1981)

Thomas D. Sharkey, Klaus Raschke,

1 MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing, Michigan 488242 

2 Present address: Research School of Biological Sciences, Australian National University, P.O. Box 475, Canberra City, ACT 2601, Australia.

3 Present address: Pflanzenphysiologisches Institut der Universität Göttingen, Untere Karspüle 2, 3400 Göttingen, Federal Republic of Germany.


In Plant Physiol 68: 1170–1174 – DOI: https://doi.org/10.1104/pp.68.5.1170



Flux response curves were determined at 16 wavelengths of light for the conductance for water vapor of the lower epidermis of detached leaves of Xanthium strumarium L.

An action spectrum of stomatal opening resulted in which blue light (wavelengths between 430 and 460 nanometers) was nearly ten times more effective than red light (wavelengths between 630 and 680 nanometers) in producing a conductance of 15 centimoles per square meter per second. Stomata responded only slightly to green light.

An action spectrum of stomatal responses to red light corresponded to that of CO2 assimilation; the inhibitors of photosynthetic electron transport, cyanazine (2-chloro-4[1-cyano-1-methylethylamino]-6-ethylamino-s-triazine) and 3-(3,4-dichlorophenyl)-1,1-dimethylurea, eliminated the response to red light. This indicates that light absorption by chlorophyll is the cause of stomatal sensitivity to red light.

Determination of flux response curves on leaves in the normal position (upper epidermis facing the light) or in the inverted position (lower epidermis facing the light) led to the conclusion that the photoreceptors for blue as well as for red light are located on or near the surfaces of the leaves; presumably they are in the guard cells themselves.

Published by

Willem Van Cotthem

Honorary Professor of Botany, University of Ghent (Belgium). Scientific Consultant for Desertification and Sustainable Development.

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