Question

Difference between Rhizome and bulb?

Answer 1

Rhizome and bulb are examples of underground stem modification. Ginger is the example of rhizome while the onion is the example of a bulb.

Complete answer:

Rhizome: A rhizome is a well-developed underground stem. The shape of a rhizome is irregular and flattened. Usually, rhizomes grow horizontally. It bears nodes and internodes, and is presented in the edges like - ginger. In rhizome, eyes like structure are formed from where the formation of a new stem takes place. A new plant can grow from these nodes and internodes.
The rhizome contains terminal buds and axillary buds. It will help it to develop into branches which grow upwards into the air and produce normal foliage leaves.
The main functioning of the rhizome is that the food material is stored in the entire stem and branches of the plant, examples are - ginger, turmeric, hops.
Bulb: A bulb is an underground modified bud with a reduced stem and a fleshy scaly leaf growing from it. It is a short underground stem with inner fleshy and dry from outer leaves. In the bulb, the stem reduces to a conical disc. The adventitious roots are produced on the lower side of the stem.
There are two types of bulb –
1. Tunicated - When the leaves are arranged in concentric form and covered by a thin paper covering to protect, is known as a tunic. E.g. – onion.
2. Scaly -The scaly leaves do not have the common center. Their leaves are small, separated and narrow. E.g.- garlic.
Sometimes axillary buds produce a daughter bulb as we can see in garlic. The functioning of the bulb is, food material stored in the skin or scaly leaves, like - onion.

Rhizome	Bulb
It is the thick underground stem.	The stem is reduced.
It is irregular and flattened.	It is globe shaped.
It contains nodes and internodes.	Nodes and internodes are absent.
The food is stored in the entire rhizome in the form of starch.	The starch is stored only in the scaly leaves.
Examples- Ginger, lotus, Asparagus.	Examples- Garlic, tulip.

Note: Axillary bud is present at the axil of a leaf and is able to produce the new shoot. The nodes are the part of the stem in which leaves are present while the internodes are the space present between two nodes. The main function of the scaly leaf is to provide protection to the axillary bud.