Question

Read the following matches.

i.	Lily	Compound tunicated bulb
ii.	Potato	Tuber
iii.	Allium cepa	Simple tunicated bulb
iv.	Allium sativum	Scaly bulb

Which of these is correct?
A. (i),(ii) and (iii)
B. (ii),(iii) and (iv)
C. (ii) and (iii)
D. (iii) and (iv)

Answer 1

Hint: Sucker, rhizome, corm, tuber, and bulb are the five different modifications of the underground stem. Underground stems lack root cap and root hair. They have a terminal bulb, nodes and internodes, scale leaves, and axillary buds. Hence, they can be differentiated from roots.

Complete answer:
Tuber or the stem tuber an oval or spherical underground swollen stem structure. It lacks adventitious roots. A corky skin having lenticels cover the stem tubers. Suckers or solons are special narrow underground branches from where the tubers arise. Spirally arranged depressions called eyes are present in tubers. Potato is an example of a tuber. The fact that the tuber of the potato is a stem can be recognized by the presence of apical buds, nodes and internodes, and eyes.
Bulbs are the underground pyriform-spherical structures which are of two types- tunicated and scaly. Dry membranous scales called tunic to cover the tunicated bulbs. In scaly bulbs, the tunic is absent. Tunicated bulbs are further classified into-
(i) Simple tunicated bulb
(ii)Compound tunicated bulb.
An example of a simple tunicated bulb is Allium cepa or onion. A whitish or pinkish tunic covers the bulb. The leaf bases in the outer part and the scale leaves in the center are represented by the fleshy scales. They occur in a concentric manner.
Thus, the correct option is C, i.e., (ii) and (iii).

Note: A tuber and a bulb have many differences. While a plant can have numerous tubers, only a single bulb can be present in a bulb. Roots are absent in tubers. A bulb has roots at its base. A tuber has external buds while a bulb has internal buds. In a tuber, the stem is enlarged while in a bulb the stem is reduced and discoid.