Direct responses of stomata to light

Stomatal responses to light

Sharkey T. D., Ogawa T. (1987)

Thomas D. Sharkey, Ogawa Teruo,

In : Stomatal Function, ed. E Zeiger, G Farquhar, I Cowan, pp. 195–208. Stanford, CA: Stanford Univ. Press –

Abstract : 

Evidence for the direct response of stomata to light in species such as maize and Eucalyptus pauciflora is reviewed and evidence of a red-light and a blue-light receptor for this direct response in wheat and the orchids Paphiopedilum and Phragmipedium is presented. Mechanisms of stomatal opening are discussed.

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:


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.

Stomatal conductance and photosynthesis



Stomatal conductance and photosynthesis 

by Farquhar G. D.Sharkey T. D. (1982)

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in Annual Review of Plant Physiology 33317345 –

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Direct and indirect effects of light on stomata

Photo credit : Google

Perilla frutescens – Shiso Perilla Magilla – Beefsteak Plant , Ji Soo , Wild basil


Separation and measurement of direct and indirect effects of light on stomata

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

Thomas D. Sharkey, Klaus Raschke,

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. 68:33–40. – DOI: 10.2307/3670169


Conductance for water vapor, assimilation of CO2, and intercellular CO2 concentration of leaves of five species were determined at various irradiances and ambient CO2 concentrations. Conductance and assimilation were then plotted as functions of irradiance and intercellular CO2 concentration. The slopes of these curves allowed us to estimate infinitesimal changes in conductance (and assimilation) that occurred when irradiance changed and intercellular CO2 concentration was constant, and when CO2 concentration changed and irradiance was constant.
On leaves of Xanthium strumarium L., Gossypium hirsutum L., Phaseolus vulgaris L., and Perilla frutescens (L.), Britt., the stomatal response to light was determined to be mainly a direct response to light and to a small extent only a response to changes in intercellular CO2 concentration. This was also true for stomata of Zea mays L., except at irradiances < 150 watts per square meter, when stomata responded primarily to the depletion of the intercellular spaces of CO2 which in turn was caused by changes in the assimilation of CO2.
Stomata responded to light even in leaves whose net exchange of CO2 was reduced to zero through application of the inhibitor of photosynthetic electron transport, cyanazine (2-chloro-4[1-cyano-1-methylethylamino]-6-ethylamino-S-triazine). When leaves were inverted and irradiated on the abaxial surface, conductance decreased in the shaded and increased in the illuminated epidermis, indicating that the photoreceptor pigment(s) involved are located in the epidermis (presumably in the guard cells).
In leaves of X. strumarium, the direct effect of light on conductance is primarily a response to blue light. Stomatal responses to CO2 and to light opposed each other. In X. strumarium, stomatal opening in response to light was strongest in CO2 free air and saturated at lower irradiances than in CO2 containing air.
Conversely, stomatal closure in response to CO2 was strongest in darkness and it decreased as irradiance increased. In X. strumarium, P. vulgaris, and P. frutescens, an irradiance of 300 watts per square meter was sufficient to eliminate the stomatal response to CO2 altogether. Application of abscisic acid, or an increase in vapor pressure deficit, or a decrease in leaf temperature reduced the stomatal conductance at light saturation, but when the data were normalized with respect to the conductance at the highest irradiance, the various curves were congruent.

Stomatal behavior in flacca, a mutant of tomato



Gas exchange, stomatal behaviour, and δ13C values of the flacca tomato mutant in relation to abscisic acid.

by Bradford K. J., Sharkey T. D., Farquhar G. D. (1983)

Kent J. BradfordThomas D. SharkeyGraham D. Farquhar,

in Plant Physiol 72 245–250 – DOI:

[PMC free article] [PubMed]


The relationship between stomatal conductance and capacity for assimilation was investigated in flacca, a mutant of tomato (Lycopersicon esculentum Mill.) that has abnormal stomatal behavior and low abscisic acid (ABA) content. The assimilation capacity, determined by measuring assimilation rate as a function of intercellular CO(2) pressure, did not differ in leaves of flacca and its parent variety, Rheinlands Ruhm (RR).

On the other hand, stomatal conductance of flacca leaves was greater than that of RR, and could be phenotypically reverted by spraying with 30 micromolar ABA. Stomatal conductance of flacca leaves was also reduced by increasing CO(2) pressure, increasing leaf to air vapor pressure difference, and decreasing quantum flux, irrespective of ABA treatment.

The high conductance of flacca leaves resulted in a high intercellular CO(2) pressure. This allowed greater discrimination against (13)CO(2), as evidenced by more negative delta (13)C values for flacca as compared to RR. The delta (13)C values of both flacca and RR plants as influenced by ABA treatment were consistent with predictions based on gas exchange measurements, using a recent model of discrimination.

Full text: Plant Physiology