Question

Question: Stilt roots grow from
(a) Lower internodes
(b) Lower nodes
(c) Upper nodes
(d) Upper internodes

Answer 1

Hint: Roots are the parts of the plants that develop from the radicle of the embryo. Their primary functions are anchorage and absorption of water from the soil. But depending on different requirements, they may be modified and stilt roots are one such modification. They are roots that grow from the first few parts of the stem from where leaves or roots grow.

Complete answer:
Stilt roots are the roots that arise from the lower nodes on the stem and they grow downwards in an oblique fashion and penetrate the soil. They provide additional mechanical support to the plant. Such type of adaptation helps the plant to withstand strong gusts of wind. This type of roots is found in many mangroves and certain crops like sugarcane and maize.
Other types of modifications of roots may be present to serve specific functions. Some of the examples of root modifications are:
- Respiratory roots or pneumatophores: They are present in plants growing in marshes and mangroves. These roots have pores at their ends and rise from the surface back to the atmosphere. They help in respiration.
- Epiphytic roots: These roots are found on plants that grow on other plants as commensals. These roots contain velamen which absorbs moisture from the atmosphere which compensates for the plant's water requirement.
- Storage roots: Certain plants have bulbous roots that are used to store reserve food material in the tissues.
- Prop roots: Another modified type of root which provides support. These roots arise from the branches and grow vertically downwards to enter the ground and provide mechanical support.
So, the correct answer is, ‘(b) Lower nodes’.

Note:
- Nodes are the places on the shoot where new growth is seen. They are the places from new leaves, branches, or adventitious roots are seen.
- Internodes are the slender portions of the stem between two nodes.
- These nodes and internodes together form the inflorescence of a plant and depending on how the buds arise from the nodes and the internodes, the inflorescence can be of various types like racemose, cymose, etc.