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Structure, Number, Distribution and Type of Stomata

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Stomata: Structure, Number, Distribution and Type of Stomata | Transpiration

by Kumar S. (2015)


in Biology Discussion, 26 Oct. 2015 –

Let us make in-depth study of the structure, number, distribution and types of stomata.

Stomata was discovered by Pfeffer & name ‘stomata’ was given by Malphigii. Stomata cover 1-2% of leaf area. It is minute pore present in soft aerial parts of the plant. Algae, fungi and submerged plants do not possess stomata.

(a) Stomata are minute pores of eliptical shape, consists of two specialized epidermal cell called guard cells.

(b) The guard cells are kidney shape in dicotyledon and dumbell shape in monocotyledon.

(c) The wall of the guard cell surrounding the pore is thicken and inelastic due to rest of the walls are thin, elastic and semi-permeable.

(d) Each guard cell has a cytoplasmic lining, central vacuole. It cytoplasm contains single nucleus and number of chloroplast. The chloroplast of guard cell are capable of very poor photosynthesis, because the absence of RUBISCO enzyme.

(e) Guard cells are surrounded by modified epidermal cells, known as subsidiary cells or accessory cells, which supports in the movement of guard cells.

(f) The Size and shape of stoma and guard cell vary from plant to plant. When fully open, the stomatal pore measures 3-12 in width and 10-40 in length.

(g) In many gymnosperms and xerophytic plants {plants growing in desert), the stomata are present embedded deeply in the leaves, so that they are not exposed to sunlight directly. Such deeply embedded stomata are called sunken stomata. This is an adaptation to check excessive transpiration in these plants.




Biologists Discover Origin of Stomata

Origin and function of stomata in the moss Physcomitrella patens


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)

in Nature Plants, 2, 16179. doi:10.1038/nplants.2016.179

See :


An international team has discovered a genetic mechanism that is responsible for the development of stomata – microscopic valves on the surface of plants that facilitate the uptake of carbon dioxide and the release of oxygen and water vapor. The researchers discovered this mechanism, which was previously known in flowering plants like Arabidopsis thaliana, in the moss Physcomitrella patens and found similarities between the two, implying that it already existed in the last common ancestor of mosses and flowering plants. The team was led by the biologists Professor Ralf Reski from the University of Freiburg/Germany and Professor David J. Beerling from the University of Sheffield/UK. The results were published in the journal Nature Plants.

Stomata came into being more than 400 million years ago, when the first plants colonized the hitherto hostile land masses. Because stomata facilitate an efficient gas exchange with the atmosphere, they enabled the spread of plants and the subsequent evolution of our complex ecosystems. In contrast to more developed vascular plants with roots, stems, leaves, and vasculature, which are necessary for the transport of water and nutrients, it remained unclear in the case of mosses, which have no vasculature, which genes are responsible for the development of stomata.

The research team found that an interaction between the two proteins PpSMF1 and PpSCRM1 in Physcomitrella is the trigger responsible for the development of stomata in moss. When they deleted one of these genes, moss developed without stomata. The researchers found that this mechanism is similar to the interaction of the two proteins MUTE and FAMA, which triggers the development of stomata in Arabidopsis. The genes which encode these proteins therefore originate from the last common ancestor of mosses and flowering plants – the prehistoric plants which left the fresh water to dwell on rocks and thus laid the foundation for the development of all current ecosystems on the mainland.


Stomatal structure and physiology

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Azizah I. R. et al. (2017)

Isabella Rahma Azizah, Silvia Ayu Budiarti, Robby Ramadhani, Sukorini Ayu Alifiah, Nurul Wulandari, Yuike Dwi Yulinar, Ajeng Selvyana Pangestu,

in Departemen Biologi, Fakultas Ilmu Alam, Institut Teknologi Sepuluh NopemberSurabaya 2017 –

Stomata adalah celah atau lubang yang berada padaorgan tumbuhan yang berwarna hijau yakni daun. Stotamadibatasi oleh sel khusus yang disebut sel penjaga atau sel penutup dan dikelilingi oleh sel tetangga. Peran penting stomata yaitu sebagai pertukaran gas O2 dan CO2 sebagai hasil dari fotosintesis dan respirasi aerob, penguapan atau transpirasi, serta mencegah kehilangan air. Praktikum ini bertujuan untukmengetahui pengaruh tekanan turgor terhadap membuka danmenutupnya stomata. Praktikum ini dilakukan pengamatan terhadap membukadan menutupnya stomata pada Rhoeo discolor.  Pengamatandilakukan secara langsung menggunakan mikroskop terhadap sayatan daun Rhoeo discolor untuk mengamati stomatanya.Sayatan daun Rhoeo discolor diberi perlakuan terhadap air danlarutan gula, kemudian menghitung pengaruhnya terhadapmembuka atau menutupnya stomata dan menghitung jumlahnya. Hasil praktikum menunjukkan bahwa stomata yang diberi perlakuan dengan tetesan air lebih banyak yang terbukadaripada tertutup. Stomata yang diberi perlakuan larutan gulamenunjukkan banyak stomata yang tertutup daripada yangterbuka, karena konsentrasi larutan gula lebih tinggidibandingkan cairan intersel sehingga cairan didalam selhipotonis dan diluar sel menjadi hipertonis. Kemudian airmengakibatkan sel penjaga menjadi flacid dan menutup.

Definition, Types and Functions of Stomata



Stomata: Definition, Types and Functions (with Diagrams) | Botany

by Gupta H. (    )

Harika Gupta,

Let us learn about Stomata. After reading this article you will learn about: 1. Definition of Stomata 2. Types of Stomata 3. Top function of Stomata.

Definition of Stomata:

The stomata are minute pores which occur in the epidermis of the plants. Each stoma remains surrounded by two kidneys or bean shaped epidermal cells the guard cells. The stomata may occur on any part of a plant except the roots. The epidermal cells bordering the guard cells are called accessory cells or subsidiary cells.

Root hairs

Generally the term stoma is applied to the stomatal opening and the guard cells. The guard cells are living and contain chloroplasts in them. They also contain a larger proportion of protoplasm than other epidermal cells. Usually in the leaves of dicotyledons the stomata remain scattered whereas in the leaves of monocotyldons they are arranged in parallel rows.

Development of root hair from protruded cells

The number of stomata may also range on the surface of a single leaf from a few thousand to hundreds of thousands per square centimetre. Stomata occur on both upper and lower surfaces of leaf, but especially they are confined to the lower surface. In floating leaves Stomata are confined only on the upper surface of the leaf.

Under normal conditions the stomata remain closed in the absence of light or in night or remain open in the presence of light or in day time. Structurally the stomata may be of different types.

Types of Stomata:

The epidermis-stomata

The Epidermis

1. Ranunculaceous or Anomocytic:

Type A — (Anomocytic = irregular celled). In this type the stoma remains surrounded by a limited number of subsidiary cells which are quite alike the remaining epidermal cells. The accessory or subsidiary cells are five in number.




Guard cells of Vicia faba


2. Cruciferous or Anisocytic:


Type B – (Anisocytic = unequal celled). In this type stoma remains surrounded by three accessory or subsidiary cells of which one is distinctly smaller than the other two.

3. Rubiaceous or Paracytic:

Type C – (Paracytic = parallel celled). In this type, the stoma remains surrounded by two subsidiary or accessory cells which are parallel to the long axis of the pore and guard cells.

4. Caryophyllaceous or Diacytic:

Type D – (Diacytic = cross celled)-In this type the stoma remains surrounded by a pair of subsidiary or accessory cells and whose common wall is at right angles to the guard cells.

Stomata-types of stomata

5. Gramineous:

The gramineous stoma possesses guard cells of which the middle portions are much narrower than the ends so that the cells appear in surface view like dump-bells. They are commonly found in Gramineae and Cyperaceae of monocotyledons.

6. Coniferous Stomata:

They are sunken and appear as though suspended from the subsidiary cells arching over them. In their median parts the guard cells are elliptical in section and have narrow lumina. At their ends they have wider lumina and are triangular in section. The characteristic of these guard cells is that their walls and those of the subsidiary cells are partly lignified and partly non-lignified.

Top function of Stomata:

They are used for the exchange of gases in between the plant and atmos­phere. To facilitate this function, each stoma opens in a sub-stomatal chamber or respiratory cavity. Evaporation of water also takes place through stomata.Sunken stoma

Sensor that shows when a plant needs water

MIT engineers create sensor that shows when a plant needs water

Kristin Toussaint

in Metro, Nov. 2017

The technology can predict droughts and let farmers and gardeners know when their plants are dying, long before they wilt.

Some people have a green thumb, and others forget to water their houseplants and garden plots until all the leaves are wilting and it’s too late to save them.

But what if your plant could tell you when it needs water? That may be the future, thanks to engineers at the Massachusetts Institute of Technology.

MIT engineers have developed a sensor that can be “printed” onto a plant’s leaf and transmit data from the plant itself about if it’s experiencing water stress.

That sensor contains electronic circuit nanotechnology and is about five times thinner than a human hair, said Michael Strano, an MIT chemical engineering professor and the senior author of the new study on the development. The sensor sits on top of the plant’s “stomata,” the small pores found on leaves.

“If you look on the surface of a leaf, you’ll see millions of little pores that actually look like eyes, and they actually open and close in real time,” he said.

MIT chemical engineers have developed a sensor that detects the opening and closing of plant stomata. Gif Courtesy of Volodymyr Koman/MIT Chemical Engineering


These pores help hydrate the plant by opening to evaporate water. “You can think of it as the plant is drinking,” Strano said. “It evaporates water through the pore and that evaporation pulls water up from the soil.”

Plants start to die from lack of water days before they visibly wilt, if they even wilt at all, Strano said — and these pores show the earliest signs of drought. To develop this technology, Strano and his coauthor Volodymyr Koman stopped watering a peace lily plant and noticed a change in how those pores function.


Subsidiaries according to interstomatal space relationships

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Classification of subsidiaries according to interstomatal space relationships

by Ramayya N., Rajagopal T. (1980)

Osmania University, Hyderabad, India


in Current Science 49(11): 671-673 –

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