Lenticels and stomata are both structures involved in gas exchange in plants, but they differ significantly in their location, structure, and function.
Key Differences Between Lenticels and Stomata
The primary differences between lenticels and stomata can be summarized as follows:
| Feature | Lenticels | Stomata |
|---|---|---|
| Location | Stems, branches, and roots of woody plants | Primarily on leaves, but also on some stems |
| Structure | Raised, corky pores | Tiny pores surrounded by guard cells |
| Function | Gas exchange in woody tissues | Gas exchange and transpiration in leaves |
| Regulation | Always open | Can open and close to regulate gas exchange |
| Size | Larger than stomata | Smaller than lenticels |
Detailed Explanation
Lenticels
- Location: Lenticels are found on the bark of woody stems and roots of dicotyledonous flowering plants and gymnosperms. They are essentially small, raised areas on the bark.
- Structure: Lenticels consist of loosely arranged cells (complementary cells) that create air spaces. They develop beneath stomata during the formation of the periderm (outer bark).
- Function: The primary function of lenticels is to facilitate gas exchange between the internal tissues of the stem or root and the atmosphere. This is crucial for respiration in woody tissues that are otherwise impermeable to gases due to the presence of a thick bark layer.
- Regulation: Lenticels are generally always open, providing continuous gas exchange. The degree of opening can vary slightly depending on the environmental conditions and the plant species, but they do not have an active closing mechanism like stomata.
Stomata
- Location: Stomata are primarily found on the epidermis (outer layer) of leaves. They can also be present on the epidermis of some stems, especially in herbaceous plants.
- Structure: Each stoma consists of a pore surrounded by two specialized cells called guard cells. The guard cells regulate the opening and closing of the stomatal pore.
- Function: Stomata are responsible for gas exchange (carbon dioxide uptake for photosynthesis and oxygen release) and transpiration (water vapor release) in plants.
- Regulation: Stomata can open and close in response to various environmental factors, such as light intensity, carbon dioxide concentration, water availability, and temperature. This regulation allows plants to control the rate of gas exchange and water loss. Guard cells control the stomatal aperature.
Summary
In essence, lenticels provide gas exchange for woody tissues, while stomata primarily facilitate gas exchange and transpiration in leaves, with the added functionality of regulating these processes via guard cell control.
