The one-celled condition in stomata of Funaria (Musci)


Incomplete cytokinesis in Funaria stomata

by Sack F. D., Paolillo D. J. (1985)

in Am J Bot 1985, 72:1325-1333. –

Publisher Full Text –


The development of the one-celled condition in Funaria (Musci) stomata was investigated using light and electron microscopy. The guard cell parent cell is unusual in that it undergoes karyokinesis but incomplete cytokinesis. The septal wall, and the cell plate from which it forms, have incurved edges in contact with the polar cytoplasm.
No evidence was found to support Haberlandt’s claim that the stomate is initially two celled but undergoes wall resorption. Preprophase microtubule bands appear to be present in nonstomatal epidermal cells with normal cytokinesis, but the possibility is raised that they are absent in guard cell parent cells.

400 million years of stomata


Regulatory mechanism controlling stomatal behavior conserved across 400 million years of land plant evolution

by Chater C., Kamisugi Y., Movahedi M., Fleming A., Cuming C., Gray J. E.,  Beerling D. J.  (2011)

in Current Biology 21 : 1025 – 1029 –  – doi: 10.1016/j.cub.2011.04.032. –


Stomatal pores evolved more than 410 million years ago [1, 2] and allowed vascular plants to regulate transpirational water loss during the uptake of CO(2) for photosynthesis [3].

Here, we show that stomata on the sporophytes of the moss Physcomitrella patens [2] respond to environmental signals in a similar way to those of flowering plants [4] and that a homolog of a key signaling component in the vascular plant drought hormone abscisic acid (ABA) response [5] is involved in stomatal control in mosses.

Cross-species complementation experiments reveal that the stomatal ABA response of a flowering plant (Arabidopsis thaliana) mutant, lacking the ABA-regulatory protein kinase OPEN STOMATA 1 (OST1) [6], is rescued by substitution with the moss P. patens homolog, PpOST1-1, which evolved more than 400 million years earlier.

We further demonstrate through the targeted knockout of the PpOST1-1 gene in P. patens that its role in guard cell closure is conserved, with stomata of mutant mosses exhibiting a significantly attenuated ABA response.

Our analyses indicate that core regulatory components involved in guard cell ABA signaling of flowering plants are operational in mosses and likely originated in the last common ancestor of these lineages more than 400 million years ago [7], prior to the evolution of ferns [8, 9].

Stomatal control and gene signalling networks in bryophytes and lycophytes


Early evolutionary acquisition of stomatal control and development gene signalling networks.

by Chater C., Gray J. E., Beerling D. J. (2013)

Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, UK.

in Current Opinion in Plant Biology 16 : 638 – 646  – doi: 10.1016/j.pbi.2013.06.013. –


Fossil stomata of early vascular land plants date back over 418 million years and exhibit properties suggesting that they were operational, including differentially thickened guard cells and sub-stomatal chambers.

Molecular studies on basal land plant groups (bryophytes and lycophytes) provide insight into the core genes involved in sensing and translating changes in the drought hormone abscisic acid (ABA), light and concentration of CO2 into changes in stomatal aperture.

These studies indicate that early land plants probably possessed the genetic tool kits for stomata to actively respond to environmental/endogenous cues. With these ancestral molecular genetic tool kits in place, stomatal regulation of plant carbon and water relations may have became progressively more effective as hydraulic systems evolved in seed plant lineages.

Gene expression and cross-species gene complementation studies suggest that the pathway regulating stomatal fate may also have been conserved across land plant evolution.

This emerging area offers a fascinating glimpse into the potential genetic tool kits used by the earliest vascular land plants to build and operate the stomata preserved in the fossil record.


Stomata in British bryophytes. I. Occurrence and structure.


The occurrence, structure and functions of the stomata in British bryophytes. I. Occurrence and structure.

by Paton J. A. (1957)

Jean A. Paton

in Transactions of the British Bryological Society, 3: 228–242. –


Stomata in the moss Physcomitrella patens

Photo credit: Google

Genetic analysis of DEK1 Loop function in three-dimensional body patterning in Physcomitrella patens

Origin and function of stomata in the moss Physcomitrella patens

by Chater C., Caine R. S., Tomek M., Wallace S., Kamisugi Y., Cuming A. C., Lang D., MacAlister C. A., Casson S., Bergmann D. C., Decker E. L., Frank W., Gray J. E., Fleming A., Reski R., Beerling D.J. (2016)

Caspar C. Chater, Universidad Nacional Autónoma de Mexico, Cuernavaca, Mexico
Robert S. Caine, University of Sheffield, UK

Marta Tomek, University of Freiburg, Germany

Simon Wallace, Royal College of Veterinary Surgeons, London, UK (University of Iowa)

Yasuko Kamisugi, University of Leeds, UK

Andrew C. Cuming, University of Leeds, UK

Daniel Lang, University of Freiburg, Germany
Cora A. MacAlister, University of Michigan, Ann Arbor, USA
Stuart Casson, University of Sheffield, UK
Dominique C. Bergmann, Stanford University, California, USA
Eva L. Decker, University of Freiburg, Germany
Wolfgang Frank, Ludwig-Maximilians- Universität München, Germany
Julie E. Gray, University of Sheffield, UK
Andrew Fleming, University of Sheffield, UK
Ralf Reski, University of Freiburg, Germany
David J Beerling, University of Sheffield, UK


in Nature Plants 2(12):16179 · November 2016 – DOI: 10.1038/NPLANTS.2016.179


Stomata are microscopic valves on plant surfaces that originated over 400 million years (Myr) ago and facilitated the greening of Earth’s continents by permitting efficient shoot– atmosphere gas exchange and plant hydration. However, the core genetic machinery regulating stomatal development in non-vascular land plants is poorly understood and their function has remained a matter of debate for a century.

Here, we show that genes encoding the two basic helix–loop–helix proteins PpSMF1 (SPEECH, MUTE and FAMA-like) and PpSCREAM1 (SCRM1) in the moss Physcomitrella patens are orthologous to transcriptional regulators of stomatal development in the flowering plant Arabidopsis thaliana and essential for stomata formation in moss.

Targeted P. patens knockout mutants lacking either PpSMF1 or PpSCRM1 develop gametophytes indistinguishable from wild-type plants but mutant sporophytes lack stomata.

Protein–protein interaction assays reveal heterodimerization between PpSMF1 and PpSCRM1, which, together with moss–angiosperm gene complementations, suggests deep functional conservation of the heterodimeric SMF1 and SCRM1 unit is required to activate transcription for moss stomatal development, as in A. thaliana. Moreover, stomata-less sporophytes of ΔPpSMF1 and ΔPpSCRM1 mutants exhibited delayed dehiscence, implying stomata might have promoted dehiscence in the first complex land-plant sporophytes.

A simple mechanism to place stomata away from each other



Early land plants evolved a simple but effective mechanism to place stomata away from each other


Amelia Merced, University of Puerto Rico, Medical Sciences Campus
Stomata are one of the key evolutionary features responsible for the successful colonization of land by plants. A stoma is a pore surrounded by a pair of guard cells, when these cells are turgid and inflated the pore opens and when cells deflate the pore is closed. This simple mechanism allows plants to optimize the amount of CO2 acquired for photosynthesis while reducing water loss due to transpiration. Spacing of stomata in the epidermis, the external protective tissue of the plant, is important to ensure proper function and carbon fixation efficiency.
Fig. 1. Diagram of a stoma with an open and close pore. Stomata distribution at the base of the capsule of the moss Funaria.
Mosses are of one of the first groups of plants to evolve stomata. Different from most plants, stomata of mosses and other early land plants are not located in leaves but on the spore producing capsule. Our study investigated if the patterning and distribution of stomata in capsules of the moss Funaria follows a similar mechanism to that of flowering plants. In flowering plants, namely the model organism Arabidopsis, stomata are place away from each other by a series of cell divisions of meristemoids, cells that actively divide to produce more meristemoids, epidermal cells or guard cells. This developmental process is regulated by genes and influence by the environment. This study shows that stomata in mosses do not require meristemoids, instead stomata differentiate before the capsule begins to expand. Cells that will become stomata are align in files and separated by at least one cell. After the fate of the future stomata is decided, the surrounding cells divide perpendicular to it and differentiate into epidermal cells. Having stomata differentiate first, ensures that around 96-99% of stomata do not touch each other.

Early land plants evolved a simple but effective mechanism to place stomata away from each other. Available from: [accessed Nov 23, 2016].

Stomata in Funaria (Bryophyta)


On the functioning of stomates in Funaria.

by Garner D., Paolillo D. J. (1973)

Dorothy L. B. Garner
Dominick J. Paolillo, Jr.


in Bryologist, 76: 423–427. – DOI: 10.2307/3241726 –


The stomates in sporophytes of Funaria hygrometrica open during the 4th day of capsule expansion, under greenhouse conditions. From the 5th through the 10th days after initial capsule expansion all stomates respond to darkness by closing.
The stomates can be reopened by light and closed by the application of abscisic acid.
We conclude that at this stage of capsule development the behavior of stomates in Funaria parallels the behavior of stomates in flowering plants.
The responsiveness of stomates to environmental stimuli declines as the capsule ripens, and in the late stages of ripening about half of the stomates remain open in the light and in the dark.