Lenticels

Definition

Lenticels are small openings found on the stems and leaves of woody plants that facilitate gas exchange between the internal tissues and the atmosphere. These structures allow for the diffusion of oxygen and carbon dioxide, playing a crucial role in the plant's respiratory process, especially in areas where the bark has thickened and traditional stomata may be less effective.

5 Must Know Facts For Your Next Test

1. Lenticels are formed as a result of cell division in the periderm, allowing for spaces that connect to internal tissues.
2. These structures vary in shape and size depending on the species of plant and are often visible as small dots or pores on the surface of the bark.
3. In addition to oxygen and carbon dioxide, lenticels can also facilitate the release of water vapor, helping to regulate moisture levels within the plant.
4. During periods of dormancy, such as winter, lenticels remain active, allowing for gas exchange even when leaves are not present.
5. Damage to lenticels can impair a plant's ability to respire effectively, leading to stress or decline in health.

Review Questions

• How do lenticels contribute to the overall gas exchange process in woody plants?
  • Lenticels play a vital role in facilitating gas exchange by providing openings through which oxygen can enter and carbon dioxide can exit internal plant tissues. This process is essential for respiration, particularly in woody plants where thick bark may limit other forms of gas exchange. Lenticels complement the function of stomata found on leaves, ensuring that gas exchange continues effectively even when leaves are absent or during periods of dormancy.
• Discuss the relationship between lenticels and the periderm in woody plants.
  • Lenticels are closely associated with the periderm, which is the protective tissue that replaces the epidermis as a woody plant matures. The formation of lenticels occurs within this peridermal layer, as it develops through cell division. The presence of lenticels within the periderm allows for gas exchange to occur despite the thickened outer bark, ensuring that internal tissues receive necessary gases for respiration while being shielded from external threats.
• Evaluate how environmental factors might influence the function and development of lenticels in different plant species.
  • Environmental factors such as humidity, temperature, and atmospheric pressure can significantly influence the function and development of lenticels. For instance, higher humidity levels may promote more active gas exchange through lenticels, while extreme dryness could limit their effectiveness. Additionally, species adapted to specific environments may exhibit variations in lenticel size and density to optimize their gas exchange capabilities under those conditions. Evaluating these adaptations helps understand how plants have evolved mechanisms for survival in diverse habitats.

Related terms

stomata:

Tiny openings on the surfaces of leaves that allow for gas exchange and water vapor release in plants.

periderm:

The protective layer of tissue that replaces the epidermis in woody plants as they grow, which contains lenticels.

xylem:

Vascular tissue in plants responsible for the transport of water and minerals from roots to other parts of the plant.