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Stomata Structure and Types

  • Botany
  • Lets learn about more stomata structure and types. After reading this article you will learn about: definition, type, top function of stomata.

Stomata Structure and Types

Definition

  • The stomata form tiny pores that are found in the epidermis plants. Each stoma is enclosed by two kidneys, or bean-shaped epidermal cells called guard cells. Stomata’s can be found in any part of the plant, excluding the roots. The epidermal cells that surround these cells known as the accessory cell or subsidiary cells.
Type of Stomata

Root hairs, A. Growth in hair, B. Growth is moist soil, C and D. Growth in dry Soil. Image Source: https://www.plantscience4u.com/

  • Generally, the term stoma can be used to describe the opening of the stomatal and guard cells. The guard cells live and have chloroplasts within them. They also have a higher percentage of protoplasm than any other epidermal cell. In dicotyledons leaves, the stomata stay scattered, while those of monocotyledons’ leaves they are placed in rows that are parallel.
Type of Stomata

Development of root hair from protruded cells, A,C, Cyperus, B and D Anigozanthos

  • Stomata numbers can vary across the surface of a single leaf, ranging from several thousand up to hundreds of thousand per centimetre. Stomata can be found on both the upper and lower sides of the leaf, however, they are found on the lower portion of the leaf. On floating leaves, Stomata are restricted to the upper side that is the surface of the leaf.
  • Under normal conditions , the stomata stay closed in absence of light, or at the dark, or are open when there is sunlight or in the daytime. The stomata can be structurally of various types.

Stomata Types

Anomocytic Stomata

  • Type A (Anomocytic = irregularly shaped). The skin stomata is enclosed by a small number of sub-cells that are very similar to the rest of the epidermal cells. The subsidiary cells, also known as accessory cells are five in total.

Anisocytic Stomata

  • Type B – (Anisocytic = unequal celled). In this kind of stomata, it is in the midst of three secondary cells or accessory cells, one of which is significantly smaller than the two other.

Type of Stomata. Image Source: https://www.plantscience4u.com/

Paracytic Stomata

  • The Type C (Paracytic = parallel-celled). In this form the stomata is enclosed by two accessory or subsidiary cells that run parallel to the longitudinal axis of guard and pore cells.

Diacytic Stomata

  • Type D (Diacytic = crossed celled)-In this form, the stomata is enclosed by a pair of accessory or secondary cells the common wall of these cells is located directly opposite to the cells that guard it.

Actinocytic

  • These stomata are surrounded by four or more subsidiary cells, elongated radially to the stomata. Example: Araceae, Musaceae, Commelinaceae

Cyclocytic

  • The stomata are surrounded by four or more subsidiary cells arranged in a narrow ring around the stoma. Example: Palmae, Pandanus, Cyclanthaceae.

Graminaceous

  • The stomatal guard cells are dumb bell shaped. They are surrounded by subsidiary cells which are lying parallel to the long axis of the pore. Example: In the members of Poaceae and cyperaceae

Function

  • They’re used to facilitate the exchange of gases between the atmosphere and the plant. To aid in this process each stoma can be opened into an sub-stomatal (also known as the respiratory cavity). The evaporation of water takes place via the stomata.

Further Readings