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Leaf Structures That Conserve Water

Leaves have numerous structures that regulate the process of photosynthesis, which plants use to make food. An important part of photosynthesis is water, and plants must conserve water to have enough during dry periods. Numerous plant structures aid in conserving water, but three major leaf parts control water conservation directly: the waxy cuticle, the stomata and the guard cells.

Waxy Cuticle And Epidermis
- The epidermis forms the outer layers of the leave, providing a shield against the outside world and helping keep water in the leaf. The epidermal cells of a leaf produce a waxy coating known as the waxy cuticle, which helps seal the epidermal layer so water doesn't exit the leaf once it is inside.
Stomata and Transpiration
- Stomata are a type of pore that controls gas exchange. When the plant needs to take in carbon dioxide, the stomata open. While this is happening, water vapor can escape through the stomata, a process known as transpiration. The amount of water lost depends on the environment around the leaf, including humidity level and air pressure.
Guard Cells
- Located on the epidermis, guard cells control the opening and closing of stomata. These cells respond to internal stimuli, such as the plant's need for carbon dioxide, and external stimuli, such as humidity. Although some water vapor is lost due to transpiration, the opening of stomata is a necessary process because the waxy cuticle would otherwise prevent gas exchange.

Nature