Question

Given are some differences between an underground stem and a root. Select the option that identifies the incorrect pair of differences.

Underground stem	Root
(i)	It is differentiated into nodes and internodes	It is not differentiated into nodes and internodes
(ii)	Scale leaves are present at the nodes.	Scale leaves are absent in roots.
(iii)	Axillary buds are present in the axil of scale leaves	Axillary buds are present at root tips
(iv)	Branches arise exogenously	Branches arise endogenously
(v)	Flowers and fruits absent	Flowers and fruits are absent.
(vi)	These usually perform the function of food storage.	These usually perform the function of food storage.

a. (i), (ii),and (vi)
b. (i), (ii), and (iii)
c. (iii), (v), and (vi)
d. (ii),(iii), (v) , and (vi)

Answer 1

Hint: Underground stems are modified plants that are developed from stem tissue but present under the soil surface. The elongation of the radicle leads to the formation of the primary root. The stems have buds that may be terminal or axillary whereas the roots do not have buds. Stems also bear fruits and flowers whereas roots do not have.

Complete answer:
The stem is the ascending part of the axis bearing branches, leaves, flowers, and fruits. It is developed from the plumule of a germinating seed embryo The stem bears nodes and internodes. It bears buds, which may be terminal or axillary. To spread out branches bearing leaves, flowers, and fruits is the main function of stems. Some stems have the function of food storage, support, protection.

The direct elongation of the radicle leads to the formation of the primary root and which grows inside the soil. It contains lateral roots of various orders that are called secondary, tertiary, etc. roots. Roots are developed from the base of the stem and constitute the fibrous root system. It does not bear fruits or flowers. The root is covered by the apex by a root cap. The main function of the root systems is the absorption of water and minerals from the soil.

Hence, the correct answer is option (C).

Note: Roots in some plants change their shape and structure and become modified to perform functions other than absorption and conduction of water and minerals like prop roots, stilt roots, and pneumatophores. Stems are also modified to perform different functions like tendrils, which help plants to climb.