Question

Raj observed that when plants grow older, certain changes are made in the epidermis. A secondary meristem strip called A replaces the epidermis and is responsible for width of the plant. B is a tissue which forms the outer covering of stems and roots of woody plants.It is made up of cork that consists of several layers of irregular cells and has deposition of substance C.
a) Identify A,B and C.
b) Mention the function of layer B.
c) What makes onion bulb water proof? Name the deposition.
d) Which part of cinchona tree is used in the preparation of anti-malaria drug Quinine?

Answer 1

Answer:

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Answer 2

Cork, Cork cambium and suberin are A , B , C respectively.

Explanation:

• Cork is the strip of secondary meristem strip which replaces the epidermis and is responsible for width of the plant. Therefore A is referred to as the cork.
• Cork cambium is the outer covering of stems and roots of woody plants. B is Cork cambium.
• C is called suberin. It is the deposition formed in cork cambium which makes it impermeable to water and various gases.
• (b) Function of layer B : Cork cambium is a lateral meristem and helps in the secondary growth of plant and is present in stem and roots of woody plants , dicots and monocots.
• (c) Suberin deposition makes the onion bulb water proof as it is a chemical which is impervious to water and gases.