Question

Fiber( longest plant cell) belongs to which tissue?
A. Parenchyma
B. Collenchyma
C. Sclerenchyma
D. Aerenchyma

Answer 1

Hint: Fiber cells have highly thickened cell walls made up of lignin. Lumen is highly reduced during maturation and these cells lost protoplasm and become dead. Fiber cells constituted the dead mechanical tissue.

Complete answer:
Permanent tissues are basically of two types
1.Simple permanent tissue: Simple tissues are made of only one type of cells. one type means the cells of this tissue are structurally and functionally similar to one another.
Mainly three types of simple tissues are present in plants these are
(a) Parenchyma: This tissue is made up of thin-walled cells which are generally isodiametric in nature.
The cells of parenchyma tissues do not lose protoplasm hence the parenchyma is a living tissue.
(b) Collenchyma: Cells of the collenchyma tissues are called collenchymatous cells, they may be spherical, oval or elongated in shape.
In collenchyma tissue cells are closely packed so intercellular space is absent. The collenchymatous cells are thickened at the corners due to deposition of cellulose, hemicellulose and pectin.
(c) Sclerenchyma: The cells of sclerenchyma tissue are called sclerenchymatous cells, during maturation these cells life protoplasm and become dead. Their cell wall is made of lignin .lignin provides mechanical strength to the plants.

On the basis of origin development, origin and structure sclerenchyma cells are further of two types.
1.Fiberes: These are highly elongated cells and they oblique or pointed ends. These are thick-walled sclerenchymatous cells with the highly reduced lumen due to a highly lignified cell wall made up of lignin.
2. Sclereids: These cells have highly thickened walls and have obliterated lumen. These are dead cells, they may be spherical, oval or cylindrical in shape and are commonly found in hard parts of plants.

Hence the correct option is sclerenchyma (C).

Note: Parenchyma and collenchyma living tissue but sclerenchyma is dead.
Collenchyma is a living mechanical tissue but sclerenchyma is dead mechanical tissue.
Aerenchyma: It is a type of parenchyma tissue which is found in hydrophytes (Plants that live in water)In these tissues large air cavities are formed which are filled with air this provides buoyancy to the plants.
Meristematic cells differentiate to form different types of permanent tissue.
Chlorenchyma-Parenchyma cells that contain chloroplast are called chlorenchyma.