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Sclerenchyma is the tissue which makes the plant hard and stiff. Sclerenchyma is the supporting tissue in plants. Two types of sclerenchyma cells exist: fibers cellular and sclereids. Their cell walls consist of cellulose, hemicellulose, and lignin. Sclerenchyma cells are the principal supporting cells in plant tissues that have ceased elongation.
They are typically 1 mm (0.039 in) in length and are thus named fiberlike sclereids. These sclereids permeate the mesophyll as a dense mat. [ 5 ] During sclerification these fiberlike sclereid cells can increase by several hundred times their original size, compared to other parenchyma cells that only increase by two or three times.
The pericycle is a cylinder of parenchyma or sclerenchyma cells that lies just inside the endodermis and is the outer most part of the stele of plants. [ citation needed ] Although it is composed of non-vascular parenchyma cells, it's still considered part of the vascular cylinder because it arises from the procambium as do the vascular tissues ...
Cross-section of a flax plant stem: 1. Pith 2. Protoxylem 3. Xylem I 4. Phloem I 5. Sclerenchyma 6. Cortex 7. Epidermis. In botany, a cortex is an outer layer of a stem or root in a vascular plant, lying below the epidermis but outside of the vascular bundles. [1]
[5] There are usually three basic types of protostele: haplostele – consisting of a cylindrical core of xylem surrounded by a ring of phloem. An endodermis generally surrounds the stele. A centrarch (protoxylem in the center of a metaxylem cylinder) haplostele is prevalent in members of the rhyniophyte grade, such as Rhynia. [6]
The epidermis is the outermost cell layer of the primary plant body. In some older works the cells of the leaf epidermis have been regarded as specialized parenchyma cells, [1] but the established modern preference has long been to classify the epidermis as dermal tissue, [2] whereas parenchyma is classified as ground tissue. [3]
Albuminous cells have long, unspecialized areas with ends that overlap with those of other sieve cells and contain nutrients and store food in order to nourish tissues. [5] They enable the sieve cells to be connected to parenchyma, functional tissue in the organs, which helps to stabilize the tissue and transport nutrients.
[5] The fossil record shows three different types of tracheid cells found in early plants, which were classified as S-type, G-type and P-type. The first two of them were lignified and had pores to facilitate the transportation of water between cells. The P-type tracheid cells had pits similar to extant plant tracheids.