Plants, like animals, have a tissue called epidermis that involves your body. The plant epidermis, which is the outermost cell layer of the plant's primary body, covers flowers, fruits, seeds, leaves, stems and roots and remains until replaced by the peridermis in growing plants secondary.
At plant epidermis cells, which originate from the protoderm, usually do not have chlorophyll and are live, flat, with large vacuoles and very juxtaposed, ie, very close to each other. The epidermis, in most cases, is formed by only one layer of cells, but there are some species that have more than one layer of this tissue. In these cases, we say that it is a multi-stratified epidermis.
The epidermis is a complex tissue, presenting, therefore, several different cell types, such as the stomata and trichomes. You stomata they are structures formed by two guard cells that delimit an opening called an ostiolus. In addition, cells associated with guard cells that are named subsidiary cells may be present. These structures are related to gas exchange and, therefore, are directly linked to the process of
photosynthesis.In addition to the stomata, it is common to find in the epidermis the presence of trichomes. These structures vary widely from plant to plant and can even be used as a taxonomic feature. Trichomes can be composed of one or more cells and are responsible for the production (glandular trichomes) or not (tector trichomes) of substances.
You glandular trichomes they produce different substances that act by inhibiting the action of herbivores or helping to capture prey, as is the case with carnivorous plants. You trichomes, in turn, despite not producing substances, they also act against herbivory, in addition to helping against excessive water loss. There is also a special type of trichome, the root hairs or root trichomes, which act in the absorption of water and nutrients by the root.
The trichome above is a tector type, as it does not secrete substances
The presence of cutina, a lipid substance in the walls of epidermal cells. The main function of this substance, which forms the cuticle, is to act as a protective layer against excessive water loss, in addition to protecting against excess solar radiation. Above the cuticle, you can also find a layer of wax. The cutin with the wax provides protection against fungi, bacteria and some insects.
The main function of the epidermis is the coating, preventing the action of pathogenic agents, reducing injury from mechanical shocks and preventing water loss. Furthermore, it is also related to gas exchange, due to the presence of stomata, protection against herbivory and loss of water due to the presence of trichomes.
By Ma. Vanessa dos Santos
Source: Brazil School - https://brasilescola.uol.com.br/biologia/epiderme-vegetal.htm
