Functions and physiology of Bryophyta stomata



The occurrence, structure and functions of the stomata in British bryophytes. II. Functions and physiology.

by Paton J. A., Pearce J. V. (1957)

in Transactions of the British Bryological Society, 3: 242–259 –

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Ontogenetic stomatal types in the Angiosperms (in Spanish)



Los tipos de desarollo estomatico en las Angiospermas

por Roth I., Clausnitzer I. (1969)

Instituto Experimental Jardín Botánico “Dr. Tobías Lasser”

Ingrid Roth,  Ingrid Clausnitzer

in Acto Bot. Venez. 4: 259-292 –


1) En el desarrollo del aparato estomático se reconocen dos tipos principales: el tipo perigéneo de las células auxiliares en el cual las células acompañantes se originan de células epidérmicas vecinas a la célula madre de las oclusivas y el tipo mesogéneo en el cual se forman tanto las células acompañantes como las oclusivas de la misma célula madre
2) El tipo perigéneo encontrado principalmente en las monocotiledóneas (Gramíneas, Commelinaceae, Palmae, Marantaqeae, Musaceae etc.) se divide en cuatro subtipos:
a) El subtipo de Saccharum, común de la mayoría de las gramineae, en el cual las células acompañantes se inician en células epidérmicas de dos diferentes hileras celulares adyacentes a la hilera de la cual procede la célula madre de las oclusivas.
b) El subtipo de Pariana en el cual se forman también dos células acompañantes que proceden de la célula epidérmica superior e inferior adyacentes a la célula madre de las oclusivas, es decir que se forman de la misma hilera celular que el estoma el cual está dispuesto perpendicular a las hileras longitudinales de células epidérmicas.
c) El subtipo de Rhoeo discolor y de las Commelinaceae en general en el cual se forman cuatro células acompañantes de cuatro diferentes células epidérmicas adyacentes a la célula madre de las oclusivas (dos laterales, una superior y una inferior).
d) Por último, el subtipo actinocítico que es característico de las dicotiledóneas; aqui las células epidérmicas que rodean la célula madre de las oclusivas se alargan radialmente y se dividen a lo largo de los radios de un círculo formando un dibujo de estrella alrededor de la célula madre central; en este caso, las relaciones entre estoma y células acompañantes son menos estrictas, ya que esta agrupación de células se encuenta también alrededor de pelos e idioblastos.
3) El tipo mesogéneo puede subdividirse en cuatro ubtipos:
a) El subtipo lateral-paralelo de dos caras en el cual la célula madre se divide a manera de una célula inicial que forma segmentos en dos caras produciendo células acompañantes hacia ambos lados; el número de células acompañantes puede variar entre dos y seis.
b) El subtipo perpendicular o transversal en el cual la célula madre se divide de la misma manera que en a), pero el poro está perpendicular al eje divisorio de las células acompañantes (en vez de paralelamente como en a), ya que en la última división que da origen a las dos células oclusivas el eje divisorio da una vuelta de 90°. Por lo tanto, consideramos el subtipo lateral-paralelo y el subtipo perpendicular como dos variaciones de la misma forma fundamental.
c) El subtipo espiral, realizado p. e. en Sedum en el cual la célula madre triangular forma segmentos sucesivamente a lo largo de las tres caras siguiendo un espiral; el modo de división es comparable al mismo de una célula inicial que se divide a tres caras. Como caso deducido del subtipo espiral consideramos la forma con tres células acompañantes que rodean a la célula madre de las oclusivas; se supone que se trata de una reducción del número de las células acompañantes.
d) El suptipo irregular en el cual se inician las células acompañantes de la misma célula madre que las oclusivas, pero el número de las células acompañantes, su disposición y el modo de dividirse de la célula madre es indefinido.
4) Los tiops de desarrollo hallados por nosotras coinciden muy bien con los tipos establecidos a base de la forma adulta del aparato estomático. El tipo de Saccharum coincide con el tipo de las gramíneas de Stebbins & Khush. El tipo de Rhoeo discolor coincide con los dos tipos de cuatro o más células acompañantes (Rhoco, palmae) de Stebbins y Khush. El tipo lateral-paralelo coincide con el tipo paracítico de Metcalfe & Chalk; el tipo perpendicular o transversal coincide con el tipo diacítico de Mefcalfe & Chalk; el tipo espiral coincide con el tipo anisocítico de Metcalfe & Chalk; y el tipo irregular coincide más o menos con el tipo anomicítico de Metcalfe & Chalk.
5) Las divisiones desiguales (Bünning 1953) son muy comunes en la formación de las células acompañantes, especialmente de las Gramineae, Commelinaceae y otras monocotiledóneas.

Stomatal patterns of dicotyledons and monocotyledons



Stomatal patterns of dicotyledons and monocotyledons

by Dunn D. B., Sharma G. K., Campbell C. C. (1965)

University of Missouri, Columbia, USA

David B. Dunn, Gopal K. Sharma, Charles C. Campbell

in Am. Midl. Nat. 74: 185-195. – DOI: 10.2307/2423132 –


After studying 443 species (226 dicots and 217 monocots) of 152 genera in 96 families, we have attempted to analyze the cuticular imprint differences between the two major groups of phanerogams.
Ten species were used in a statistical analysis of the variation of stomatal size and frequency.
Eleven species are illustrated by photographs of the plastic imprints of the cuticular characters. These were selected to represent trees, woody vines, suffrutescent, herbaceous and aquatic dicotyledons.
The only monocotyledons illustrated are those with net venation. A brief key is presented to emphasize the differences as well as the exceptions.
The authors conclude that in dicotyledons the stomata are usually of four or more ages and sizes, and that size is an unreliable taxonomic character.
In contrast, stomatal size in monocotyledons is relatively reliable, there being a single size class for each species. No two genera of the 152 studied were alike in their cuticular characteristics.

Stomatal adjustment to water transport capacity



Stomatal and hydraulic conductance in growing sugarcane: stomatal adjustment to water transport capacity.

by Meinzer F. C., Grantz D. A. (1990)

Hawaiian Sugar Planters’ Association, P.O. Box 1057, Aiea, HI 96701, U.S.A.

in Plant Cell Environ 13: 383–388 – DOI: 10.1111/j.1365-3040.1990.tb02142.x –

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Stomatal conductance per unit leaf area in well-irrigated field- and greenhouse-grown sugarcane increased with leaf area up to 0.2 m2 plant 1, then declined so that maximum transpiration per plant tended to saturate rather than increase linearly with further increase in leaf area.

Conductance to liquid water transport exhibited parallel changes with plant size. This coordination of vapour phase and liquid phase conductances resulted in a balance between water loss and water transport capacity, maintaining leaf water status remarkably constant over a wide range of plant size and growing conditions.

The changes in stomatal conductance were not related to plant or leaf age. Partial defoliation caused rapid increases in stomatal conductance, to re-establish the original relationship with remaining leaf area. Similarly, pruning of roots caused rapid reductions in stomatal conductance, which maintained or improved leaf water status.

These results suggest that sugarcane stomata adjusted to the ratio of total hydraulic conductance to total transpiring leaf area. This could be mediated by root metabolites in the transpiration stream, whose delivery per unit leaf area would be a function of the relative magnitudes of root system size, transpiration rate and leaf area.

Malic and citric acids provide much of the counter ion for the K(+) taken up during stomatal opening



Organic-acid and potassium accumulation in guard cells during stomatal opening

Outlaw W. H., Lowry O. H. (1977)

Department of Pharmacology, Washington University School of Medicine, St. Louis, Missouri 63110.

in Proceedings of the National Academy of Sciences, USA 74: 44344438 -PMID: 16592449 PMCID: PMC431957 – 

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Leaflets of Vicia faba L. with either open or closed stomata were quick-frozen and freeze-dried. Individual guard cell pairs and pure samples of palisade parenchyma, spongy parenchyma, and epidermis lacking guard cells were dissected from the leaflets, weighed, and assayed for organic acids or K(+).K(+) was measured by a new enzymatic method.

In guard cells of open stomata, as compared to closed stomata, K(+) was 2- to 4-fold higher, malic acid 6-fold higher, and citric acid 3-fold higher. Both aspartic and glutamic acids were also higher, but the amounts present were low compared to malic and citric acids.

Isocitric acid was significantly higher in one experiment, but not in another. Glyceric acid was not increased. Succinic acid was too low to detect by the method used; but in guard cells of open stomata the concentration must have been less than 2% of that of malic acid. Malic acid was higher in the palisade parenchyma from the leaflet with open stomata. The ion balance shows that malic and citric acids provide much of the counter ion for the K(+) taken up during stomatal opening.

The vacuole in differentiating stomata undergoes two major changes in morphology



The vacuole system in stomatal cells of Allium  Vacuole movements and changes in morphology in differentiating cells as revealed by epifluorescence, video and electron-microscopy.

by Palevitz B. A., O’Kane D. J., Korbes R. E., Raikhel N. V. (1981)

in Protoplasma 109: 2355.- 

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The development of autofluorescent vacuoles in the stomatal cells of Allium cepa and A. vineale was investigated using fluorescence microscopy of live cells, low light level television, cytochemistry and electron microscopy.

During cell differentiation, the vacuole undergoes two major changes in morphology. In an intermediate form, it consists of a reticulum or network of interlinked tubules and small chambers. The network is formed from globular cisternae in very young GMCs and is maintained as a reticulum until it is transformed back into a globular form later in the differentiation of guard cells.

The network thus remains intact through the course of one cell division. During its existence, the reticulum undergoes complex movements and rearrangements. The significance of these changes in the vacuole is discussed in terms of vacuole ontogeny and function and the mechanisms that control motility in plant cells.

Plasmodesmata and the mechanism of stomatal movements.



Electron microscopic evidence for plasmodesmata in dicotyledonous guard cells.

by Pallas J. E. Jr., Mollenhauer H. H. (1972)

in Sci. 175, 1275–1276 -DOI: 10.1126/science.175.4027.1275 –

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In Nicotianna tobaccum and Vicia faba leaves, plasmodesmata were observed by electron microscopy in walls between sister guard cells and walls between guard and epidermal cells.

The latter were found primarily in pit fields of anticlinal walls and showed considerable complexity as evidenced by branching. Cytologically, the plasmodesmata appear functional in operative guard cells and should be considered in the mechanism of stomatal movements.