Question

A simple mechanical tissue devoid of lignin is
A. Chlorenchyma
B. Collenchyma
C. Sclerenchyma
D. None of the above

Answer 1

Hint:Tissues are classified into two main groups like meristematic tissues (which consists of the young actively dividing cells) and Permanent tissue (which is also called mature tissues, these tissues do not divide further). They are two kinds of permanent tissues - Simple tissues and Complex tissues.

Complete answer:Simple permanent tissues made up of only one type of cells which are structurally as well as functionally similar. They are three types- parenchyma, collenchyma, and sclerenchyma. Collenchyma is derived from the Greek word Kolla- glue, enchyma-tissue. These cells occur in layers or patches below the epidermis in the outer part of the herbaceous stem, petiole, and leave midrib. They are present only in the primary body. This tissue contains cells that are thickened in corners on the cell walls due to the accumulation of cellulose, hemicellulose, and pectin. They do not have intercellular spaces. These are living cells, have protoplasm, and contain chloroplasts. The shape of collenchyma cells is oval, spherical, and polygonal. The lines in stems of celery are a distinguished example of collenchyma tissue. Functions of collenchyma are: they provide mechanical strength, rigidity, and support to the growing parts of the plants such as branches of young stem and petiole of a leaf. Chloroplast containing collenchyma is responsible for photosynthesis. This tissue resists the tearing effects of wind on the leaves due to its presence along the margin of leaves.

Hence, the correct answer is Option-B collenchyma.

Note: The main difference between sclerenchyma cells and collenchyma cells are, sclerenchyma cells are non-living, supporting cells with highly lignified thick cell walls. Whereas, collenchyma cells are living supporting cells with angular thickness in the primary cell wall.