The following points highlight the top eight types of stoma in the epidermis. The types are: 1. Anomocytic 2. Anisocytic 3. Paracytic 4. Diacytic 5. Actinocytic 6. The stomata are minute pores which occur in the epidermis of the plants. Stomata. Guard cells of Vicia faba. Epidermis. 2. Cruciferous or Anisocytic. Anomocytic. Stomata are with few surrounding cells which are undifferen- tiated from the normal epidermal cells (Fig. 1I). Anomotetracytic.

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In monocotsseveral different types of stomata occur such as:. As a result the stomatal complex has square appearance in surface view. It is also reported from dicotyledons, e. It is to note that Metcalfe and Chalk in the original definition of actinocytic did not state the number of subsidiary cells that enclose a stoma. This increase in solute concentration lowers the water potential inside the cell, which results in the diffusion of water into the cell through osmosis.

Not to be confused with Stroma. In vascular plants the number, size and distribution of stomata varies widely. The two polar subsidiary cells are often smaller. Predicting how stomata perform during adaptation is useful for understanding the productivity of plant systems for both natural and agricultural systems. It is based on the size, shape and arrangement of the subsidiary cells that surround the two guard cells.

Then, because of rings of cellulose microfibrils that prevent the width of the guard cells from swelling, and thus only allow the extra turgor pressure to elongate the guard cells, whose ends are held firmly in place by surrounding epidermal cells, the two guard cells lengthen by bowing apart from one another, creating an open pore through which gas can move.

Commelina of the same family has six subsidiary cells. The two guard cells of stoma remain surrounded by two subsidiary cells each being present on each lateral side of guard cells. In this type the stoma remains surrounded by a limited number of subsidiary cells which are quite alike the remaining epidermal cells. Members of Zingiberaceae and. In addition to gramineous stoma Metcalfe described a new stomatal type in monocotyledons.


After reading this article you will learn about: Evaporation of water also takes place through stomata.

Retrieved May 6, As a result, the PEPCase alternative is preferable only where water is limiting but light is plentiful, or where high temperatures increase the solubility of oxygen relative to that of carbon dioxide, magnifying RuBisCo’s oxygenation problem.

The inverse of r is conductance to water vapor stomatqso the equation can be rearranged to; [14].

Definition | Paracytic stomata

Glinus latioides and Trianthema lancastrum etc. Retrieving the products of carbon anomoccytic from PEPCase is an energy-intensive process, however. The seven types of stoma five from dicotyledons and two from monocotyledons according to Metcalfe and Chalk and Metcalfe are shown in Fig. The subsidiary cells of Drvnys and Linum etc.

Top 8 Types of Stoma in the Epidermis | Plants

The roundish cells occur at the ends and other two elongated subsidiary cells are present on the lateral sides of the paired guard cells. It is termed tetracytic where the guard cells are surrounded by four subsidiary cells —two laterals and two polar, each being present on the four sides. In this type of stoma there are four subsidiary cells, which are annomocytic in two different ways: A group of mostly desert plants called “CAM” plants Crassulacean acid metabolismafter the family Crassulaceae, which includes the species in which the CAM process was first discovered open their stomata at night when water evaporates more slowly from leaves for a given degree of stomatal openinguse PEPcarboxylase to fix carbon dioxide and store the products in large vacuoles.

Usually in the leaves of dicotyledons the stomata remain scattered whereas in the leaves of monocotyldons they are xnomocytic in parallel rows. Each stoma is guarded sttomata two specialised epidermal cells, called guard cells.


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. The guard cells are living and contain chloroplasts in them.

Anomocytc two reniform guard cells of stoma remain surrounded by subsidiary cells that are in number. The characteristic of these guard cells is that their walls and those of the subsidiary cells are partly lignified and partly non-lignified. Types of Stomata 3.

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Diacytic stoma remains surrounded by a pair of subsidiary cells. The loss of these solutes causes an increase in water potentialwhich results in the diffusion of water back out of the cell by osmosis. Apocynaceae, Boraginaceae, Chenopodiaceae, Cucurbita etc.

A Perspective for the Twenty-First Century”. The degree of stomatal resistance can be determined by measuring leaf gas exchange of a leaf. Generally the term stoma is applied to the stomatal opening and the guard cells.

Answer Now and help others. There are no subsidiary cells in this type of stoma and the stomatal complex consists of two guard cells only. The two guard cells of a stoma are without any subsidiary cells.

This saturates RuBisCO with carbon dioxide, allowing minimal photorespiration.

Ancistrocladus and Euclea pseudebenus Ebenaceae. Stomatal crypts are sunken areas of the leaf epidermis which form a chamber-like structure that contains one or more stomata and sometimes trichomes or accumulations of wax.

Leaves, Stem, and Wood in relation to Taxonomy, with notes on economic Uses. Views Read Edit View history. Botanical terms Botanists by author abbreviation Botanical expedition.