Question

Which of the following is a subaerial stem modification with a long internode?
(a) Rhizome
(b) Offset
(c) Runner
(d) Sucker

Answer 1

Hint: The subaerial stem is a stem that remains partly in air and partly underground. It is also known as ‘Creeper'.

Complete answer: The runner is a subaerial stem modification with a long internode and a creeping stem. The nodes give rise to axillary buds, aerial branches, adventitious roots, and scaly leaves. The aerial branches arising from the nodes can detach itself to develop into a new plant. It also helps in the vegetative propagation of plants. It can be seen in Cynodon (lawn grass), Oxalis (wood sorrel), Centella, etc.

Additional Information:
Some other kinds of the modified subaerial stem are-
1. Sucker- This subaerial stem arises from the base of the stem that lies beneath the ground. After running horizontally under the ground for some distance it obliquely comes out to give new branches and roots. It is seen in Chrysanthemum, Banana, Mentha, strawberry, pineapple, etc.
2. Stolon- This weak subaerial stem arises from the base of the stem. It grows in the air for a while and after that bends downwards to touch the ground. There it gives rise to a new shoot and adventitious roots. It can be seen in Jasmine, Colocasia, Vallisneria, etc.
3. Offset- This subaerial stem is short and bears one internode only. After originating from the leaf axil, it grows a little horizontally and then produces a rosette of leaves above and roots below. It can be seen in Pistia (water lettuce), Eichhomia (water hyacinth), etc.

So, the correct answer is ‘Runner’.

Note:
1. The runner can be underground also as seen in Agropyron.
2. The term ‘creeper’ should not be confused with the term ‘climber’. The former is a horizontally running stem while the latter helps in climbing by attaching to support. Both are weak and tender.