Question

Describe modification of stem with suitable examples.

Answer 1

Hint: In some plants the stems are modified to perform tasks like storage of food, performing photosynthesis, creating a defense system, and giving support to the plant. Modification of stem takes place to suit the particular environment and habitat.

Complete answer:
The different types of modifications are:
> Rhizome- These are modified stems that grow horizontally under the ground. They have nodes and internodes. The shoots develop from the nodes vertically from the buds of the rhizome. This is seen with ginger which is a modified stem.
> Runners- In runners, the shoot grows, runs parallel to the ground and the roots are just below the nodes of the shoot. The Strawberry plant is an example of this kind.
> Corm- They contain stored food and it enables the plant to survive even in winters. They are more rounded and fleshier than the rhizomes. An example is a gladiolus.
Tubers- Some stems get modified to store food, especially starch. These stems are juicy, thick, and fleshy. An example of this is potatoes.
> Tendrils- Stems in weak plants provide support by coiling and climbing in the nearby structure. They are thin and slender. In cucumbers, melons and many other tendrils are seen.
> Thorn- A spine-like structure is seen in plants like bougainvillea and is called thorn. These protect the plants from herbivorous animals. The thorns have a sharp and pointed structure.
> Cladode- They have green stems and help in photosynthesis in the absence of the leaves. An example of this is Opuntia.

Note:
The modified stems perform special functions for the survival of the plants. The stems get modified according to the functions they perform. All the stems do not undergo the same modification.