Sclereidit

Sclereidit refers to a group of sclerenchyma cells found in plants. These cells are characterized by their thickened, lignified secondary cell walls, which provide structural support and protection. Sclereidit are typically found in various plant tissues, including bark, pith, and vascular tissues. Their presence contributes to the rigidity of plant organs like stems and leaves, and they can also play a role in defending against herbivores by making plant tissues harder to digest.

There are several types of sclereidit, distinguished by their shape and arrangement. Common forms include brachysclereids (stone cells), which are often isodiametric and found in the flesh of fruits like pears and the shells of nuts; macrosclereids, which are elongated and columnar, found in seed coats; osteosclereids, which are bone-shaped; astrosclereids, which are star-shaped and often found in leaf parenchyma; and trichosclereids, which are hair-like and can extend into intercellular spaces.

The development of sclereidit often begins with meristematic cells or parenchyma cells that undergo a process of differentiation. As they mature, their protoplasts typically degenerate, leaving behind the thick, rigid cell wall. This cell wall is infused with lignin, a complex polymer that makes it very strong and resistant to decay. Sclereidit are a vital component of a plant's mechanical support system and contribute significantly to the overall texture and durability of plant structures.