Question

Differentiate between potato tuber and tuberous root of dahlia.

Answer 1

Hint: The thickened part of an underground stem that is used to store food is called a tuber or stem tuber. They have buds from which the new plant grows. Eg: potatoes. Tuberous root is a thick fleshy root that is modified as a storage organ where one end of the root contributes for the development of shoot and the other end contributes to the development of the root. Eg: sweet potato(dahlia), carrot etc.

Complete Answer:

Sl.No	Potato tuber	Tuberous root of dahlia
1.	They are the modified stem tissues.	They are modified root tissues.
2.	It contains axillary buds on the surface.	It contains adventitious buds on the surface.
3.	It is considered as an underground stem.	It is considered as an underground root.
4.	Under a certain condition, one of the bud sprouts or develops by suppressing the other axillary buds.	Under favorable conditions, all the adventitious buds develop into leafy shoots that produce adventitious roots.
5.	Enlarged stolons are thickened to form storage organs.	Lateral roots are enlarged to form storage organs.
6.	It helps in the storage of food.	It helps in the growth of a new plant.

Note: Remember that bulb and tuber are not the same. A fleshy underground storage organ is known as a bulb. Only a few plants have true bulbs. By definition, tuberes are bulbs, but they differ in their appearance and mode of growth though both serve the same purpose of storage of food.