lenticelles

Lenticelles are small pores or openings found on the bark of woody stems and roots of plants. They are essentially gas-exchange structures that allow for the passage of oxygen into the plant tissues and carbon dioxide out. Unlike stomata, which are typically found on leaves and are surrounded by guard cells, lenticelles are composed of a mass of loosely packed cells called complementary tissue that protrude through the epidermis and outer bark.

These structures are visible to the naked eye and often appear as small dots, lines, or slightly raised areas on the bark surface. The color and shape of lenticelles can vary significantly depending on the plant species. They are crucial for the survival of woody plants, especially those that grow in waterlogged soils or have a thick, impermeable bark. Without lenticelles, the living cells within the stem and roots would be deprived of the oxygen necessary for respiration.

The arrangement and prominence of lenticelles can also be a characteristic feature used in plant identification. For example, birch trees are well-known for their prominent, horizontal lenticelles that give their bark a distinctive appearance. In some cases, lenticelles can also serve as entry points for pathogens, although their primary role remains gas exchange. They are a vital adaptation for facilitating internal respiration in woody perennial plants.