Radial structures in the stomata of Ouratea (Ochnaceae) – (in German)


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Ouratea spectabilis

Radialstrukturen in den Stomata von Ouratea spectabilis (Mart.) Engl.

by Arens T. (1968)

Thusnelda Arens

Cadeira de Botânica da Faculdade de Fil.Est. de São PauloBrasil

in Protoplasma (Wien) 66: 403-411 –



An den lebenden unbehandelten Spaltöffnungen von Ouratea spectabilis wurde eine vom Spalt ausgehende Radialstruktur beobachtet.

Dieselbe läßt sich mit verschiedenen Farbstoffen darstellen und ist nicht mit einer Cuticularstreifung identisch.

Es handelt sich um Ektodesmen, die infolge ihrer besonderen Eigenschaften (Größe usw.) ohne Anwendung spezieller Methoden sichtbar sind.

Mit der Methode von Bancher, Hölzl und Klima läßt sich zeigen, daß aus ihnen Flüssigkeitströpfchen abgeschieden werden können.

Mit dem Transpirationswasser aufgenommene Salze (Thallium und Mangan) reichern sich im Zellumen und in diesen Ektodesmen an.

Sie sind offenbar die Bahnen der peristomatären Transpiration.


Radial structures in the stomata of Ouratea spectabilis (Mart.) Engl.



In living, untreated stomata of Ouratea spectabilis a radial structure originating in the stomatal opening was observed, which may be demonstrated by means of various stains.

It is not identical with a cuticular striation.

These structures are shown to be ectodesms visible without use of special methods because of their peculiar properties (size etc.).

The method of Bancher, Hölzl and Klima allows to demonstrate that these ectodesms may secret fluid droplets. Salts (thallium and manganese) taken up with the transpiration stream are concentrated in the cell lumen and in the ectodesms. Obviously, the ectodesms are the pathways of peristomatal transpiration.

Diacytic stomata in the Nelsonioideae (Acanthaceae)

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Nelsonia campestris

Staurogyne zeylanica Kuntze – https://08511630493324166816.googlegroups.com/attach/836ccffa714d9eb8/IMG_7163.jpg?part=0.1&view=1&vt=ANaJVrHMX5IttDk0NUD664jw0rZB8913EbPdeoOREhA-b5XurMV0ZYKJU3PgRGahRjwHSf8Eh7W4HKGjJrLu6lGi_1YxFyddxkQ_wEWwat9FqKLvuqhVT5c


Cuticular studies in some Nelsonioideae (Acanthaceae)

by Ahmad K. J. (1974)


in Bot. J. Linn. Soc. 68: 73-80 – DOI: 10.1111/j.1095-8339.1974.tb01748.x – 


This paper represents a modified portion of a thesis accepted for the Ph.D. degree by the University of Lucknow.


The foliar epidermis and cuticle of Staurogyne longifolia (Nees) Kuntze, Elytraria acaulis (L.f.) Lindau var. acaulis, E. acaulis var. lyrata (Nees) Bremek. and Nelsonia campestris R.Br, have been investigated, revealing broad similarities with those of the rest of the Acanthaceae;

the presence of diacytic stomata in the Nelsonioideae is evidence of its affinity with the Acanthaceae in general, while the presence of panduriform glandular hairs and the absence of the cystoliths in Nelsonioideae indicate its particular affinity with the Thunbergioideae.

Substantial evidence is provided to support the retention of Nelsonioideae as a subfamily of the Acanthaceae, rather than its transfer to the Scrophulariaceae.


The development and structure of the guard cell walls in stomata of Funaria (Bryophyta)

Funaria hygrometrica moss – http://4.bp.blogspot.com/-uWo7qZHj0og/UcfymcnXysI/AAAAAAAABHQ/VjKvY0WfQ_o/s1500/Funaria-hygrometrica-moss.jpg


Structure and development of walls in Funaria stomata.

by Sack F. D., Paolillo D. J. (1983)

Fred D. Sack, D. J. Paolillo Jr.

in Am. J. Bot. 70, 1019–1030 –



The development and structure of the guard cell walls of Funaria hygrometrica Hedw. (Musci) were studied with the light and electron microscopes.
The stoma consists of only one, binucleate guard cell as the pore wall does not extend to the ends of the cell. The guard cell wall is thinnest in the dorsal wall near the outer wall but during movement is most likely to flex at thin areas of the outer and ventral walls.
The mature wall contains a mottled layer sandwiched between two, more fibrillar layers. The internal wall layer has sublayers with fibrils in axial and radial orientations with respect to the pore.
During substomatal cavity formation, the middle lamella is stretched into an electron dense network and into strands and sheets.
After stomatal pore formation, the subsidiary cell walls close to the guard cell become strikingly thickened.
The functional implications of these results are discussed

Protoplasmic changes during stomatal development in Bryophyta


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Funaria hygrometrica

Protoplasmic changes during stomatal development in Funaria.

by Sack F. D., Paolillo D. J. (1983)

Fred D. Sack, D. J. Paolillo Jr.

in Canadian Journal of Botany, 61: 251526 – https://doi.org/10.1139/b83-275 – 



Key protoplasmic features of stomatal development in Funaria hygrometrica Hedw. (Musci) were characterized using light and electron microscopy.

Endoplasmic reticulum (ER) cisternae are initially rough and often arranged in parallel arrays. During pore formation, the cytoplasm becomes packed with tubular, smooth ER.

Older but still functional stomata contain small amounts of primarily cisternal ER. Lipid bodies decrease in electron density when tubular ER appears.

Preliminary observations indicate that two large vacuoles occupy the polar regions of open, but not closed, stomata.

Intact plasmodesmata occur in developing but not mature walls. Plastid structure, microtubule distribution, and other protoplasmic features are essentially similar to those described in the stomata of other genera.

The morphology of the stomatal pore cuticle and peristomatal transpiration in Bryophyta



Stomatal pore and cuticle formation in Funaria.

by Sack F. D., Paolillo D. J. Jr. (1983)

Fred D. Sack, D. J. Paolillo Jr.

Boyce Thompson Institute for Plant Research and the Section of Plant Biology, Cornell University, Ithaca, USA

in Protoplasma 116 : 1 – 13 –



Cuticle and pore development in the guard cells of Funaria were investigated with the electron microscope.

Pore cuticle formation is simultaneous with the creation of the pore itself. The morphology of the pore cuticle is unlike that of any cuticle described in the literature. It has many lamellae which are penetrated by electron dense fibrils.

Three different cuticular morphologies exist from the pore to the subsidiary cell walls. The cuticles on the pore and outer walls contain fibrils that sometimes reach to the surface.

The subsidiary cell cuticle lacks fibrils altogether. It is hypothesized that (1) cuticularization of the middle lamella contributes to ventral wall separation and (2) differences in extent of cuticular fibrils are related to greater water loss from stomata than from subsidiary cells (peristomatal transpiration).

Selection pressures on stomatal evolution.



Selection pressures on stomatal evolution.

by Raven J. A. (2002)

John A. Raven

Division of Environmental and Applied Biology, School of Life Sciences, University of Dundee, Biological Sciences Institute, Dundee DD1 4HN, UK

in New Phytologist 153 : 371 – 386 – DOI: 10.1046/j.0028-646X.2001.00334.x – 



Fossil evidence shows that stomata have occurred in sporophytes and (briefly) gametophytes of embryophytes during the last 400 m yr.

Cladistic analyses with hornworts basal are consistent with a unique origin of stomata, although cladograms with hornworts as the deepest branching embryophytes require loss of stomata early in the evolution of liverworts.

Functional considerations suggest that stomata evolved from pores in the epidermis of plant organs which were at least three cell layers thick and had intercellular gas spaces and a cuticle; an endohydric conducting system would not have been necessary for low-growing rhizophytes, especially in early Palaeozoic CO2-rich atmospheres.

The ‘prestomatal state’ (pores) would have permitted higher photosynthetic rates per unit ground area. Functional stomata, and endohydry, permit the evolution of homoiohydry and the loss of vegetative desiccation tolerance and plants > 1 m tall.

Stomatal functioning would then have involved maintenance of hydration, and restricting the occurrence of xylem embolism, under relatively desiccating conditions at the expense of limiting carbon acquisition.

The time scale of environmental fluctuations over which stomatal responses can maximize carbon gain per unit water loss varies among taxa and life forms.