Question

Tissue composed of non-parenchymatous cells and have an isodiametric or irregular shape is called as
A. Sclereids
B. Sclerenchyma fibers
C. Sieve tubes
D. None of the above

Answer 1

Hint: Tissue of epidermis, ground tissue, and vascular tissues are formed of non-parenchymatous cells and have an isodiametric or irregular shape. These tissues have elaborate branches and forked types of cells with a thick cell wall.

Complete answer:
Sclereids are sclerenchyma cells of reduced form with thick and lignified cell walls which help in the formation of durable layers in many plants. These tissues are present in the form of bundles which makes the tissues highly thickened and are star-shaped. These tissues are responsible for the texture of guavas and found in seed or fruit walls of pineapple. These tissues are of irregular shape, isodiametric, highly branched, forked, and prosenchymatic. They are formed of non-parenchymatous cells and are present in a group of bundles found in the periphery. The isolated form of sclereids is called as idioblast. Sclereids are created by sclereid primordial that becomes an individual in early development. Sclereids are of different types as stem sclereids, leaf sclereids, fruit sclereids and seed sclereids. The term sclereids was given by Alexander Tschirch in 1885.

So the correct answer is Option A- Sclereids.

Note: As sclereids tissues are found at various parts of the plant body they can be differentiated by the part of the plant on which they are present. They are present in the stem as stem sclereids, in seeds as seed sclereids, in leaf as leaf sclereids, and fruits as fruit sclereids. These tissues are durable in nature and protect plants from harsh conditions as they are formed by thick bundles of on parenchyma cells and have a lignified cell wall for protection.