Question

Fibrous root system is also called
A) Tap root system
B) Tuberous root system
C) Nodulated root system
D) Adventitious root system

Answer 1

Hint: Fibrous root is the thin network of branching roots of about equal diameter which consists of many branching roots that emerge from the base of the stem rather than the radical of the seed.

Complete answer:
A) Taproot system: These are those large, central, and dominant roots that arise from the radicle of the seed and which grow deep into the soil. Many other secondary roots arise from the taproot which mostly grows laterally.
These are found in carrot, Beetroot, Sugarbeet, and many other dicot plants.
B) Tuberous root: It is a modification of tap roots which act as the organ of storage. They are thick, fleshy and without any definite shape. Example: Mirabilis jalapa (4’O plant).
C) Nodulated root: These roots are the modification of the secondary root of the taproot which occurs in the legumes (pulse family). In these roots swelling are found called nodules and these nodules harbor nitrogen-fixing bacteria Rhizobium leguminosarum . They help in fixing atmospheric nitrogen into nitrates which can be easily absorbed by the plants.
D) Adventitious root: These are those roots that arise from the plant other than the radicle of the seed.
There is much modification of adventitious root, they can be modified as storage of food (Fasciculated tuberous root in Dahlia, Nodulose root in ginger, Beaded roots in grasses, etc.), for providing support (Like prop root in a banyan tree and stilt root in maize).
Fibrous roots are those which arise from the base of the stem rather than the radicle of the seed. They are common in monocots, ferns, plants with parallel venation. And these roots grow fairly to the surface of the ground. Example: Onion, tomatoes, lettuce, lilies, corn, etc.
So the correct answer is option (D).

Note: Adventitious roots are modified for some special function also. Like Epiphytic roots and Sucking roots.
Epiphytic roots: These are found in the orchids. They grow on the branches of the big trees in the forest to get the proper amount of sunlight and roots are hanging from the plants so they are also called hanging roots and these types of plants are called Epiphytic plants.
Sucking roots: These are microscopic roots developed by the parasitic plant to suck nutrients from the host plant. These roots are also called Haustoria or Parasitic roots.