Question

What is cladode? Give an example.

Answer 1

Hint: Photosynthetic organ of a vascular plant which is flattened is called a leaf. But in some plants, other parts are also modified into photosynthetic organs.

Complete Answer:
- Flattened green stems modified into chief photosynthetic organs are called cladodes. They are green and fleshy in nature. Leaves are modified to form spines in such plants. Cladode arises from the axil of these plants. Example of such a plant is asparagus. The scales found on asparagus spears are the true leaves.
- If these spears continue to grow as thick,fleshy leaf-like structures, that becomes cladode. The presence of cladode is desert angiosperm plants are an excellent example of convergent evolution. All plants belonging to Cactaceae have cladodes. These plants have columnar, water-storing green stems, reduced leaves and protective spines and thorns.
- They are usually called stem succulents. In the case of cacti, leaves present on the main stems last for a very small time as they do not develop as scale leaves. The leaves present on axillary buds which are round cushion areas or areoles on the trunks that develop as spines.
- Example for cladode is asparagus.

Additional information: Few other kinds of leaf modifications are as follows,
1. Storage leaves - They are generally seen in xerophytic plants and they have succulent and thick leaves which stores water.
2. Tendrils - They are seen in plants with weak stems and they help them in climbing a nearby stick or a wall.
3. Spines - Leaves are modified into thorn-like structures which act as defensive structure and also reduce the water loss caused due to transpiration.

Note: In cladode a stem is modified into a photosynthetic structure whereas in phylloclade, the branch is modified into photosynthetic organs. A phyllode is a modified shoot that connects the stem to the leaf.