Stoma on the leaf of a tomato plant

Bild Photo:Leaf of a tomato plant – macroscopically and microscopically. Evaporation is vital for plants.Its leaves are covered on all surfaces by epidermal cells, which are protected by a layer of wax (cuticle) on the outside, making it hard for water vapor (as well as for oxygen and CO2) to permeate the surfaces. Gas is exchanged with the environment through stomata. These stomata consist of two bean-shaped guard cells, which regulate the gas exchange of the leaf and thus can also control the evaporation rate in the range of two orders of magnitude.Information and ideas:The microscopic photo originates from an electron microscope.