Question

Which one contains more reduced form of stem
A. Bulb
B. Rhizome
C. Tuber
D. Thinner

Answer 1

Hint: Stem of some plants are modified to do several functions. They include vegetative propagation and perennation. Both underground, aerial and subaerial stem types are modified in this kind.

Complete step by step answer:
Stem modifications are of several types. Underground stem is modified mainly for storing food. They are of four types- Rhizome, Corm, Stem tuber and Bulb. Ginger is an example for rhizomes. Amorphophallus and Colocasia are examples for Corm. Potato is the most common stem tuber and onion is an example for Bulb. Onion has the most reduced form of stem as it is a Bulb.
Subaerial stems are modified mainly for vegetative propagation and spread. They are mainly of four types. They are Runner, Offset, Stolon and Sucker.
Grass and Oxalis are examples for Runner. Pistia and Eichornia are water plants and are examples of Offset. Banana and pineapple are examples for Sucker and Stolon includes Mint and Jasmine.
Aerial stem modifications include tendril, thorn, phylloclade, bulbil etc. Gourds and grape vine are examples of stem tendril. Opuntia and Euphorbia are examples of Phylloclade. Thorn containing plants are Citrus and Bougainvillea.

Hence the correct option is A.

Additional information:
Other than stem modifications, roots and leaves of plants can be modified into several forms. Tap roots and adventitious roots of plants are often modified to perform functions other than absorption. Carrot, Radish, Sweet potato etc are examples.

Note:
The difference between a spine and a thorn. Spine is a leaf modification seen in xerophytes like cactus plants. Thorns are the stem modifications seen in plants like citrus and bougainvillea.