Kollenkíma

Kollenkíma, commonly known in English as collenchyma, is a type of plant ground tissue composed of elongated living cells with unevenly thickened primary cell walls. The thickening is not uniform; it often occurs in the corners of cells (angular collenchyma), in longitudinal bands along the walls (lamellar collenchyma), or around intercellular spaces (lacunar collenchyma). The tissue is distinguished by its flexible, yet supportive, structure.

Kollenkíma provides mechanical support to growing parts of the plant, such as stems, petioles, and young leaves, without restricting growth. Because the cells remain alive at maturity, the tissue can contribute to dynamic growth and bending as plants develop. The cell walls are rich in cellulose and pectin, and the walls are thicker than those of parenchyma but lack the highly lignified secondary walls seen in sclerenchyma.

Distribution and development vary among species, but kollenkíma is commonly found beneath the epidermis in herbaceous dicot stems and in developing regions of leaves and shoots. It forms a flexible scaffold that helps plants withstand mechanical stresses (wind, movement) while allowing continued elongation during growth. Kollenkíma develops from meristematic tissue and differentiates from other ground tissues, remaining distinct from sclerenchyma and parenchyma in both structure and function.

In contrast to parenchyma (thin-walled, living but less specialized) and sclerenchyma (thick, often lignified, providing rigid support), kollenkíma offers support that is strong yet adaptable, supporting growth and vitality in non-woody parts of plants.