Stomata

Jun-5-2008 By admin

What is a stomata, or better say what are stomata ?

Stomata are found in leaves and they are tiny pores on the surface that permit exchange of gases between the inside and the outside of the leaf. A stoma is formed by “guard cells” which are two specialized epidermal cells. The guard cells change their form to open and close the pore on a timescale of minutes. In plants stomata range between 30 - 60 micrometers long and occur at densities ranging from 50 to 200 per square mm.

The role of stomata ?

The stomata opens in order to allow CO2 to enter the leaf for the photosynthesis process. When they open, stomata also allows water vapors to get out, this means that the opening must be precise, in order to allow CO2 to enter but not to let too much water to be lost.

The way stomata works

Stomata respond to factors surrounding them, such as light, water concentration and CO2. The guard cells have highly tuned sensors that respond to these factors and they change shape and size by means of altering their solute concentration so that water is allowed to pass either way through osmosis.

General stomata information

there may be up to 6 million stomata on a regular leaf
the process of loosing water through a stomata is called transpiration
stomata on leaves can be considered a pathogenic pathway, but it was discovered that stomata sense the presence of some pathogens and deny access.

A few stomata pictures

This one is a picture representing: confocal of stomata

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Following is a picture where two stomata are visible, one on each side of the leaf section. A stoma consists of the pore itself (nr 2 in the picture) and the two surrounding guard cells ( nr 1 in the picture, only one is represented) . Also, the air space is visible(nr 3 in the picture)