kollenkym

Kollenkym, also known as collenchyma, is a simple plant tissue composed of living, elongated cells with unevenly thickened primary cell walls. The thickening is typically not lignified, and the cells remain alive at maturity. This tissue provides flexible mechanical support to growing parts of the plant.

The cells in kollenkym are usually elongated and arranged in strands or continuous cylinders, often just beneath the epidermis in stems, petioles, and young leaves. There are two common patterns of thickening: angular collenchyma, in which wall thickening occurs mainly at the corners where cells meet, and lamellar (or ladder-like) collenchyma, in which thickening occurs along the tangential walls parallel to the organ's axis.

Kollenkym develops from meristematic tissue and differentiates from parenchyma. The cells retain their cytoplasm and metabolic activity, enabling continued growth of the organ they support. Because the walls are thickened but not heavily lignified, kollenkym provides mechanical strength while remaining flexible, allowing organs to elongate without breaking.

Functionally, kollenkym.supports growing regions and helps maintain organ integrity during bending and movement, such as in young stems and developing leaves. It is often found in parts of the plant that require both support and flexibility, unlike sclerenchyma, which is rigid and usually dead at maturity, or parenchyma, which is involved in storage and metabolism.

In common plants, kollenkym is visible in structures like celery stalks, where the characteristic strands add to the stalk’s resilience.