Sclerenchyma


Also found in: Dictionary, Medical, Wikipedia.

Sclerenchyma

Single cells or aggregates of cells whose principal function is thought to be mechanical support of plants or plant parts. Sclerenchyma cells have thick secondary walls and may or may not remain alive when mature. They vary greatly in form and are of widespread occurrence in vascular plants. Two general types, sclereids and fibers, are widely recognized, but since these intergrade, the distinction is sometimes arbitrary.

Sclerenchyma

 

in plants, mechanical tissue consisting of two types of thick-walled and usually woody cells: fibers and sclereids.

The fibers are greatly elongated cells, usually ranging in length from fractions of an mm to 1 cm (nettles). Some plants, for example, the ramie, have fibers reaching 4 cm in length. The fibers have sharp ends and porous layered walls. Nonwoody fibers of sclerenchyma having cellulose walls, for example, in flax, are a valuable raw material for the textile industry. Sclerenchyma fibers are as durable as steel and as resilient and elastic as rubber. The amount and distribution of the fibers determine a plant organ’s durability when subjected to stretching, compression, and bending.

In many plants the fibers form a mechanical facing for the vascular bundles. In the stems of dicotyledons they are found mainly in the pericycle and the primary phloem. In the stems and leaves of monocotyledons the fibers often form subepidermal cords, whereas in the roots they are concentrated primarily in the center. In addition to fibers of first derivation formed from the cells of the basic meristem and procambium, the term “sclerenchyma” is also applied to phloem and xylem (libriform) fibers of cambial origin.

For information on sclereids see.

L. I. LOTOVA

sclerenchyma

[sklə′reŋ·kə·mə]
(botany)
A supporting plant tissue composed principally of sclereids whose walls are often mineralized.
References in periodicals archive ?
Sclerenchyma cells are only at the phloem poles of vascular bundles.
35 mm in diameter, with up to 9 veins; sclerenchyma forming a complete ring with a thickness of 3-5 cells, 4-5 grooves, 35 ridges (Figures 2a, 2b, 2c).
epidermis thickness, sclerenchyma cell thickness, cortical region thickness, endodermis thickness and vascular region thickness were studied to differentiate the nine cultivars of date palm, obtained from Date Palm Research Station, Jang, on the basis of their root anatomy.
16, 19, 22), and sclerenchyma sheaths shared by mid-vein vascular bundles were observed only in S.
The cross-sections, the needle width and thickness, and separately the areas of epidermis, mesophyll, xylem, phloem, and sclerenchyma were examined under microscope (Micros MC400A) at x 100 magnification and photographed with a Nikon Coolpix 5400 digital camera.
Barfod (1988, 1991) studied leaf anatomy of the genera Ammandra, Palandra, Phytelephas and identified two groups: the first includes Ammandra decasperma and Aphandra natalia, with small guard cells, thick cuticle and sclerenchyma sheath around vacular bundles; the second joins together Palandra (=Phytelephas) aequatorialis and Phytelephas karstenii, P.
It consists of parenchyma, collenchyma, and sclerenchyma cells.
Cells of the ground tissue are of three types: parenchyma, collenchyma, and sclerenchyma (See Figure 7-9).
The principal shoot is surrounded by a sheath of several layers of sclerenchyma cells.
10) However, more recent work has revealed that sphagnum stems consist of a central parenchyma of pale, isodiametric cells, a sclerenchyma of long, thick-walled cells, and a cortex of large, empty, thin-walled cells.
Lignin provides strength and rigidity to plants and to plant structures such as xylem, which allows for the transport of water: and sclerenchyma and bundle sheath cells, which provide a natural barrier to microorganisms (Bird, 1988).