Sclerenchyma
As sclerenchyma ( ancient Greek σκληρός skleros "hard" and ἐνχυμα enchyma "the entrapped") refers to a strengthening tissue in plants. It usually occurs as a layer around a vascular bundle . Sklerenchyma cells form secondarily thickened, mostly lignified cell walls. These are often reinforced with lignin , which deposits the cells to death. It can, for example, appear as a layer around a usually young vascular bundle in a shoot .
Sclerenchyma species
Scleroid
→ Main article stone cells
Sklereids, also called isodiametric sclerenchymal cells, are shorter and mostly blunt consolidation cells that form pressure-resistant shells of stone fruits and nuts. But they also come in bark, bark and in the pulp of z. B. pears before. The cell walls are heavily thickened, which only allows a small lumen inside the cell. Nevertheless, the cells are connected to the neighboring cells via speckled channels .
Sclerenchymal fibers
Sklerenchymal fibers are prosenchymatic cells and are called wood fibers in the xylem . If the sclerenchymal fibers are in the secondary phloem , they are also called bast fibers. The fibers resulting from meristematic cells, the determination in procambium has occurred. But due to the differentiation of the sclereids from cells, the cells are characterized as sclereids at an early stage. So this criterion is not always valid. The compound term fiber sclerosis can be used if difficulties arise in classifying it as fiber or scleroid.
literature
- Eckehart J. Jäger, Stefanie Neumann, Erich Ohmann: Botany . 5th revised edition. Spectrum Akademischer Verlag, Heidelberg 2009, ISBN 978-3-8274-2357-3 (reprint from 2003).
