Question

Adventitious roots are adventitious in their
a. Function
b. Position
c. Place of origin
d. Internal structure

Answer 1

Hint: The roots that do not arise from the organ of the plant root are called adventitious roots. They mainly arise from the stem, leaf. They propagate vegetatively. The life of the adventitious roots is short. They are shallow and can grow either underground or serial. For example – Ficus plants that arise free-hanging aerial roots.

Complete answer:
The adventitious roots are the ones that can arise from anywhere apart from the original producing organ of the plant (roots). The place of origin of the adventitious root is not fixed. It can arise from the stem of the plants, leaf of the plant.

The adventitious aerial roots will grow above the ground and receive their nourishment directly from the air. For example – epiphytes (orchids), banyan tree roots are strangler, mangroves in pneumatophores, mistletoe plant haustorial roots, etc.

The adventitious roots that grow underground are present on the nodes of the horizontal stem by the fibrous roots. They are mainly regarded as surface feeders.

The function of the adventitious roots is to facilitate the transport of gas and water as well as uptake of nutrients during flooding. They help in the survival of the plant. It also releases ethylene which promotes the growth of the plant and regulates it properly.

The position of arising of adventitious roots is not fixed. It can arise from any organ of a plant that does not consist of any root tissue. During normal development, its response to stress conditions such as wounding, deprivation of nutrients, etc.

The internal structure of adventitious roots is much less diverse than the stems. There is no pith and gaps, protostelic. They can grow from more than one apical initials.

Hence, the correct answer is option (C).

Note: Thus, the roots which form from non-root tissue are adventitious and they are produced by the layering of air. It is most common in tropical trees. To respond to internal and external stimuli, the adventitious roots undergo modifications and respond to different forms of it. It helps in food storage.