Question

Abnormal secondary growth in roots is found in
A. Maize
B. Beet
C. Grapes
D. Mango

Answer 1

Hint: The root system's key functions are the absorption of water and minerals from the soil, supplying the plant parts with adequate support, storing reserve food material, and synthesis of plant growth regulators.

Complete Answer:
- The root of a plant is surrounded by a small thimble-like structure called the root cap at the apex. It protects the root as it goes into the soil.
- The area of meristematic activity lies above the root cap. This region's cells are very slim, thin-walled, and have thick protoplasm. They divide repeatedly. The cells proximal to this area undergo rapid elongation and expansion and are responsible for the growth in length of the root, and are thus called elongation region.
- The cells of the elongation region slowly divide and mature. Therefore, this zone proximal to the area of elongation is called the area of maturation. Some of the root epidermal cells develop very small, thread-like known as root hairs that absorb water and minerals from the soil.
- The roots of certain plants undergo changes in their shape and structure and are modified to perform functions other than water and mineral absorption, and conduction. They are modified to store food, support, and respiration.
- The tap roots of beetroot, carrot, turnip and adventitious roots of sweet potato get swollen and store food. It arises outside of the old tissues because of the development of consecutive cambium rings.
- Or, there may be several small cambial rings outside the old tissues. These roots are high in parenchyma and have few tracheal components.

Thus, the correct answer is beet.

Note: The storage roots have extensive parenchymal and some components of trachea. These tracheal components are loosely distributed in the parenchyma. The parenchyma cells are abundant in stored food materials and thus are also known as storage parenchyma.