sklerenchymy

Sclerenchyma is a type of complex plant tissue that provides structural support and strength to plants. It is characterized by cells that have thickened, lignified secondary cell walls. These cells are typically dead at maturity, meaning they no longer possess living protoplasts, which contributes to their rigid nature. Sclerenchyma cells are essential for the overall mechanical support of non-woody parts of plants and for strengthening mature woody tissues.

There are two main types of sclerenchyma cells: fibers and sclereids. Fibers are elongated cells, typically much longer than they are wide, with tapering ends. They often occur in strands or bundles and are found in various parts of the plant, including the cortex, phloem, and pith. Sclereids, also known as stone cells, are more variable in shape and size, often appearing in irregular, star-like, or spherical forms. They are commonly found in the seed coats, fruit skins, and the hard tissues of nutshells and endocarps.

The primary function of sclerenchyma is to provide mechanical strength and support, allowing plants to withstand forces such as wind, gravity, and turgor pressure. This structural integrity is crucial for plant growth and survival. The presence of lignified cell walls also makes sclerenchyma resistant to stretching and compression. In some cases, sclerenchyma can also play a role in water transport, though this is not their primary function. The hardness of sclereids, for instance, contributes to the protective outer layers of fruits and seeds.