In some species, the first periderm appears rather deep in the stem, usually in the primary phloem viz., Berberis, and Vitis etc. Sclerenchyma is the tissue which makes the plant hard and stiff. The vein xylem transports water from the petiole throughout the lamina mesophyll, and the phloem transports sugars out of the leaf to the rest of the plant. It may terminate short of one or both ends of the cell. They are generally located in nongrowing areas of plant bodies, like mature stems or bark. Sclerenchyma tissues and conducting elements of the phloem and xylem were studied in stems in several stages of development. Sclerenchyma is the supporting tissue in plants.Two types of sclerenchyma cells exist: fibers 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. Sclerenchyma fibers cap the vascular bundles. 2.2.3 Sclerenchyma. Sclerenchyma is a specialized tissue consisting of a group of cells in which secondary walls are often lignified. In some fibers the secondary wall does not extend the full length of the cell lumen. The term Sclerenchyma is derived from the Greek word ‘skleros’ means ‘hard’ and ‘enchyma’, an ‘infusion’. Sclerenchyma (Structure, Types and Functions of Sclerenchymatous Cells in Plants) What are Sclerenchymatous Cells? The cells are nonstretchable and rigid. Sclerenchyma cells with thick cells walls that are stained red due to lignin in the cell walls. Ø Sclerenchyma is a simple permanent tissue in plants. In the center of the stem is ground tissue. Usually, mature sclerenchyma cells are dead cells that have highly thickened, lignified secondary walls. Sclerenchyma cells are found wherever a plant needs strength and support, such as fibers, stone cells, wood, and water-conducting cells. The term sclerenchyma was coined by Mettenius in 1805 and the cells are known as sclerenchymatous cells. The development of sclerenchyma cells is closely related to changes in leaf curling. There are two types of sclerenchyma cells: fibers and sclereids. The deficiency of SLL1, whose main function is to determine the development of the abaxial sclerenchyma cells of the leaf, leads to a defect in the formation of sclerenchyma cells on the abaxial side, thereby resulting in incurved leaves (Zhang et al., 2009). Sclerenchyma. They can be of two broad types: sclereids and fiber cells. They are dead at maturity. Development of Periderm: The first periderm commonly appears during the first year of growth of stem and root. In stem most usually it originates in the sub-pepidermal layer. In (b) monocot stems, vascular bundles composed of xylem and phloem tissues are scattered throughout the ground tissue. Veins are composed of xylem and phloem cells embedded in parenchyma, sometimes sclerenchyma, and surrounded by bundle sheath cells. Sclerenchyma cells have lignified cell walls. Figure 2.6.b. Ø Sclerenchymatous cells are dead at their maturity. These cells tend to have thick, lignified secondary cell walls. The bundles are smaller than in the dicot stem, and distinct layers of xylem, phloem and sclerenchyma cannot be discerned. Ø They have thick secondary cell wall. ‘The exodermis and underlying layer of heavily lignified sclerenchyma of Oryza sativa is a constitutive feature.’ ‘In Cayenne, development of a solid, lignified disk of sclerenchyma across the receptacle was positively associated with ease of separation in a comparison of an easy pick and a hard pick genotypes.’ During ontogeny the primary-phloem fibers develop a thick primary wall over which a thick secondary wall is subsequently deposited. 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