Question

Most of the economically important fibre yielding plants belong to family of
A) Malvaceae
B) Solanaceae
C) Cruciferae
D) Poaceae

Answer 1

Hint: The fibre yielding plants fulfil the second requirement of human beings, .i.e., clothing. This kind of plant has always been known to mankind since time immemorial. The flax was cultivated in Europe even in the Stone Age. Botanically fibres are sclerenchymatous taking place in different parts of the plant.

Complete answer:
A) Malvaceae –This is from a mellow family. It includes cotton, ladies finger, etc. It is the most important fibre plant which supplies more than 70% of the world consumption of fibres. Raw cotton compromises of cellulose (94%), protein (1.3%), pectic substances, water, sugar and some pigment traces. So it is the correct option.
B) Solanaceae - It is also known as potato family and includes many vegetable crops, such as brinjal, potato, tomato, green pepper, Shimla pepper etc. as well as ornamental plants, and drug plants, like tobacco. So it is the wrong answer.
C) Cruciferae -Is mustard family or cabbage family which includes vegetable and oilseed crops mainly. Thus, it is an incorrect option.
D) Poaceae –It is known as the grass family. It includes beets, bamboo etc. here we cannot find any fibre yielding plant. So it is the wrong option.

The correct option is (A) – Malvaceae.

Note:
> Plant fibre is collected from the phloem, which is called "inner bark"/ "skin" or bast surrounding the stem of certain dicotyledonous plants.
> It bears the conductive cells of the phloem and provides strength to the stem.
> Plant fibre mainly consists of cellulose and cellulose fibres. Which are usually used to make paper and cloth.