Kollenkima

Kollenkima (collenchyma) is a simple permanent plant tissue consisting of living, elongated cells with unevenly thickened primary walls. It provides structural support during plant growth, while allowing flexibility necessary for bending without breaking. The cells are alive at maturity; walls thickened principally at the corners and along certain faces, depending on type. Common wall thickening patterns are angular (thickened corners between adjacent cells) and lamellar (thickening in horizontal layers). Cells are often elongated and arranged in strands or cylinders beneath the epidermis, particularly in stems and leaf stalks.

Kollenkima is found in stems, leaves, and petioles, especially in regions that experience growth and bending, such as young shoots. It provides mechanical support to growing tissues, enabling elongation and upright posture; it is not lignified like sclerenchyma, so it remains flexible. The tissue arises from the ground meristem and forms around vascular bundles as discrete strands or continuous layers in the cortex or just beneath the epidermis.

Compared with sclerenchyma, kollenkima cells remain living and lack thick secondary walls reinforced with lignin, giving them greater elasticity. It is also distinct from parenchyma, which is typically softer and less rigid. In many herbaceous plants, kollenkima helps prevent lodging and supports young organs until lignified tissues develop, contributing to overall plant flexibility during growth.