Question

Fusiform, napiform, conical roots are the modifications of
A. Tap roots
B. Adventitious roots
C. Stilt roots
D. Aerial roots

Answer 1

Hint: Roots are cylindrical, underground and non-green parts of the plant. It is generally the descending portion of the plant axis ie., it grows downward into the soil. It lacks nodes, leaves, buds but gives rise to endogenous lateral branches.

Complete answer:
Roots move in the direction of gravity (geotropism) and against the direction of light (phototropism). Here the roots are said to be positively geotropic and negatively phototropic. Plants have well developed root systems. The main root that is the primary root along with root hairs and root tip and its lateral branches form the root system.
Now let us match this with given options :-
Tap roots :- The primary root is directly elongated from the radicle and grows inside the soil (eg. dicots), it bears lateral roots of several orders that are referred to as secondary, tertiary or The primary roots and its branches constitute the tap root system. they constitute conical roots present in carrot , fusiform root present in radish and napiform root present in turnip.
Adventitious roots :- Some plants have specialised roots called adventitious roots. The adventitious develop mainly from any parts of the plant except that of the radicle examples included. Grass, Monstera, Banyan tree.
Stilt roots :- they arise from the lower nodes of stem. They occur to support the main axis of the stem. They enter the soil obliquely. Some common examples include sugarcane and maize.
Aerial roots :- the aerial roots of Tinospora and submerged roots of Trapa become green and synthesize the food. So they become specialised in performing the function of photosynthesis.

Our required option is A) Tap roots.

Note: The roots mainly help in absorption of water through the root hairs to transport upward and minerals from the soil. Roots in some plants undergo modifications in their shape and structure in order to perform functions of big respiration, storage and protection.
Storage roots : In some plants the primary tap root is modified to store food and assumes various shapes. e.g., taproot of carrot, turnip, radish, beet and adventitious roots of sweet potato get swollen and store food.