Question

In which of the following type of underground modification of stem, storage of food does not occur in stem
(A) Bulb
(B) Rhizome
(C) Corm
(D) Tuber

Answer 1

Hint: Bulb is a short modified stem with fleshy leaves that function as storage of food during dormancy. A bulb consists of a relatively large, usually globe-shaped, underground bud with membranous or fleshy overlapping leaves arising from a short stem.

Complete answer:
Bulb is an underground stem that is usually globular in nature containing embryonic plants inside, with small leaves, flowers, stems, and roots. The leaf base of bulbs do not support leaves but contain food reserves to enable the plant to survive in adverse conditions. The contents of the bulb are enclosed with fleshy scales arising from the top which are held together by a small basal plate. The fleshy leaves are storage organs that store food and water.
There are two types of bulbs. One type has a thin paper-like covering that protects its fleshy leaves, for example, onion. The second type does not have a papery covering and has naked storage leaves that make the bulb appear to consist of a series of angular scales. Such types of scaly bulbs are seen in lilies.

The rhizome is an indefinitely growing perennial main stem that occurs underground and gives rise to annual aerial branches or leaves under favourable conditions. The rhizome is of two types:
(1) Rootstock Rhizome: The rhizome is oblique or vertical with a tip almost reaching the soil surface. It is often unbranched (except Banana), for example, fern Dryopteris.
(2) Straggling Rhizome: The rhizome is horizontal. It is often branched. Branching may be sympodial (uniparous cyme, for example, Ginger, Turmeric, Canna).
Corm: It is an annual, vertically growing, thick, swollen, spherical, or subspherical underground stem which bears circular nodes, sheathing leaf bases, and scales. Buds present on corms give rise to new aerial shoots and new corms, for example, colocasia, crocus, and freesia.
The tuber has swollen tips of underground branches that do not bear roots. Each tuber has a number of eyes. The skin has corky covering with lenticels for example potato.

So, the correct answer is option A i.e Bulb.

Note: Corm is a rounded underground storage organ present in plants used to survive in winter, consisting of a swollen stem base covered with scale leaves and buds, and, unlike in bulbs, these do not appear as visible rings when the corm is cut in half.