Definition - What does Epidermis mean?
The epidermis is an outer protective cell layer that provides protection against infection, mechanical injury and water loss in plants. It is the outermost, protoderm-derived layer of cells that covers seeds, fruits, flowers, leaves, roots, and stem parts.
In most cases, the epidermis increases water absorption, secretes substances, protects the plant from intense sunlight, and regulates transpiration.
MaximumYield explains Epidermis
The epidermis serves a variety of functions:
- Roots - Water, mineral, and nutrient absorption
- Stems, flowers, and leaves - Secretes metabolic compounds, regulates gas exchange, and protects the plant against excessive water loss
The epidermis acts as the boundary between the plant and the external environment.
The plant epidermis is divided into two parts: the lower epidermis and the upper epidermis. In between these two layers are two other tissues referred to as the ground tissue system and the vascular tissue system.
The ground tissue system also known as the mesophyll, and is responsible for plants photosynthesis. The vascular tissue system is responsible for nutrient and water transport from the roots to the other parts of the plant.
The epidermis is covered with small pores called the stomata, which are openings that facilitate the exchange of oxygen and carbon dioxide. These openings are controlled by guard cells that determine the extent to which they open and close.
The walls of the epidermis are enclosed by a cuticle. The cuticle decreases water loss to the atmosphere and in most cases is covered by a wax that acts as a moisture barrier and protects the plant from wind and dirt.