Biology · Anatomy of Flowering Plants · NEET
| State at maturity | Fibres: dead | Sclereids: dead |
| Shape | Fibres: long, narrow, thread-like with pointed ends | Sclereids: short, wide, irregular |
| Wall | Fibres: thick, lignified | Sclereids: very thick, lignified |
| Lumen | Fibres: narrow | Sclereids: very narrow |
| Found in | Fibres: stems, leaf veins, hard seed and fruit coverings (jute, hemp) | Sclereids: nut shells, seed coats, pulp of guava and pear |
Sclerenchyma is DEAD at maturity. This is the most tested point for NEET. Parenchyma and collenchyma are living, but sclerenchyma cells lose their protoplast (living content) when mature. The walls become thick and lignified, so no living matter is left inside. Remember: among the three simple tissues, only sclerenchyma is dead.
Both are sclerenchyma, both are dead and thick-walled, but their SHAPE differs. Fibres are long, narrow and thread-like with pointed ends; they occur in groups and give flexible strength (like jute and hemp fibres). Sclereids are short, wide and irregular in shape with very thick walls and a very narrow lumen; they make tissue hard. So: fibres are long threads, sclereids are short stone cells.
Sclereids are a type of sclerenchyma cell. They are dead cells with highly thickened lignified walls and a narrow lumen. They are also called stone cells or grit because they feel gritty. You find them in the hard shell of nuts, the stony endocarp (hard part) of coconut and almond, the seed coats of some seeds, and the gritty texture of guava and pear pulp. NEET 2021 directly matched 'dead cells with highly thickened walls and narrow lumen' to sclereids.
The lumen is the empty space inside the cell. In sclerenchyma the wall keeps depositing lignin, growing thicker and thicker inward. This thick wall fills up most of the cell, so the central space (lumen) becomes very narrow. A narrow lumen plus a thick lignified wall means great mechanical strength, which is why sclerenchyma supports the plant.
Sclerenchyma gives MECHANICAL SUPPORT and hardness to plant parts. Because the cells are dead with thick lignified walls, they act like the plant's skeleton. Fibres provide tensile strength (resist pulling) in stems, leaf veins and hard coverings of seeds and fruits. Sclereids provide hardness in nut shells, seed coats and fruit pulp. Sclerenchyma cannot do photosynthesis or storage; its only role is strength.
Match List-I with List-II. List-I: (a) Cells with active cell division capacity (b) Tissue having all cells similar in structure and function (c) Tissue having different type of cells (d) Dead cells with highly thickened walls and narrow lumen. List-II: (i) Vascular Tissues (ii) Meristematic tissues (iii) Sclereids (iv) Simple Tissue. Choose the correct answer:
Try the real previous-year questions from this chapter — each with the answer and a full solution.
Yes. Both fibres and sclereids are types of sclerenchyma, and both are dead at maturity with thick lignified walls. Only their shape and location differ.
Sclereids are found in the hard shells of nuts, the stony endocarp of coconut and almond, seed coats of legumes, and the gritty flesh of pear and guava fruits.
Yes. The thick walls of sclerenchyma are made hard by lignin. Lignin deposition is what kills the cell and gives it mechanical strength.
Collenchyma is living with unevenly thickened cellulose+pectin walls (support in young growing parts). Sclerenchyma is dead with thick lignified walls (support in mature hard parts).
Sclerenchyma is a SIMPLE permanent tissue because it is made of only one type of cell. Xylem and phloem are complex tissues because they have many cell types.
