Question

Select the mismatched pair out of the following
a. Rhizome- Dryopteris, Nelumbo nucifera
b. Corm- Crocus sativus, Amorphophallus
c. Sucker-Curcuma domestica, Zingiber officinale
d. Tuber- Helianthus tuberosus, Solanum tuberosum

Answer 1

Hint: We are familiar with the word Vegetative Propagation i.e. an asexual method of plant reproduction which occurs in leaves, roots and stem through fragmentation or regeneration of specific part of plant. There are two types of vegetative propagation: 1. Natural vegetative propagation- plants arising from stem are known as rhizomes, bulbs, tubers, etc. and 2. Artificial vegetative propagation- includes cutting, grafting, layering, etc. The given types are of stem modification which are especially for storage of food.

Complete answer:
The stem is a plant axis that contains shoots, leaves, buds and roots. It transports water, minerals and nutrients to other parts of the plant.
There are 3 types of stem modification: 1. Underground modification, 2. Sub-aerial modification 3. Aerial modification.
  Underground modification: Their types are: Rhizome- It is non-green and fleshy type of underground stem with nodes as well as internodes and the nodes have dry, scale leaves with axillary buds. Rhizomes grown obliquely are known as root-stock and those which are grown horizontally are known as straggling. Example: Dryopteris, Nelumbo nucifera, Alocasia, etc.
Corm- They grow in vertical direction and have a flat base and are somewhat spherical in shape. It also contains circular nodes and internodes. Example: Colocasia, Amorphophallus, Crocus sativus, etc.
 Tuber- They are used to provide energy and nutrients. It is a swollen tip of an underground stem. Example: Potatoes, Helianthus tuberosus, Solanum Tuberosum, etc.
Sub-aerial modification: Their types are: Sucker- They arise from the basal part of the main stem and grow horizontally under the soil and obliquely on the ground. Example: Apple tree, Cherry Tree, Banana tree, etc.
Stolon: It also arises from the base of the main stem . It grows aerially and then bends towards the ground.
Aerial modification: Their types are: Stem tendrils: The stem are modified to green thread like leafless structure i.e. tendrils which are used for climbing.
Thorns: They are pointed, hard and sometimes also possess leaves and flowers and they are used for defense.

Hence, option (a), (b) and (d) are the correct pair so the incorrect pair is option (c) and thus, the correct answer is option (c).

Note: Stem modification helps to transport water, for storage of food, to provide support, for vegetative propagation, protection, etc. The modified forms of root are Tap root and Adventitious root. Corm is round and it is a storage organ of the plant.