Question

Aerial stem modifications
A. Provide protection and climbing
B. Help in photosynthesis
C. Help in vegetative propagation
D. All of the above

Answer 1

Hint: Here, in this question, we need to understand the meaning of aerial modification of the stem and its functions. In addition to that, we also need to know different modifications of the stem.

Complete step-by-step answer:
Stem is divided into three major types:
1) Stem Underground Modification: Some underground stems have been modified to store food and survive in harsh environments. Underground stem modifications include bulb, corm, tuber, and so on.
2) Stem Sub-aerial Modification: The stem of these plants is partially above ground and partially below ground. These are transformed into runners, suckers, stolons, and so on.
3) Aerial Stem Modification: Climbing, food storage, vegetative propagation, and protection are all performed by stems that have been modified into aerial forms. Tendrils, thorns, hooks, phylloclade, tuberous stems, and so on are examples of stem modifications.
Aerial stem modifications are changes to the aerial stems, vegetative buds, and floral buds of plants that perform functions such as climbing, protection, support, photosynthesis, food synthesis, or vegetative propagation. Tendrils, thorns, hooks, phylloclade, tuberous stems, and bulbils are examples of aerial stem structures that undergo modifications to perform these special functions. The modified structures' axillary or terminal parts reveal their stem nature.
Certain plants modify their aerial stems or buds to perform specific functions such as climbing, protection, food storage, vegetative propagation, and so on. The stem or its branches are transformed into tendrils, which are green thread-like leafless structures used for climbing. Thorns are used as defence or climbing organs (e.g., Bougainvillaea) and to control transpiration. Phylloclades are fleshy, green flattened or cylindrical branches that can grow indefinitely. They contribute to photosynthesis and store water. Bulbils are vegetative or floral buds that have been modified with stored food and are intended for vegetative propagation.
So, option D is correct.


Note: Aerial stem alterations are changes to the aerial stems, vegetative buds, and floral buds of plants that are growing in a variety of environments and serve purposes such as climbing, protection, support, photosynthesis, food synthesis, or vegetative propagation. For this question candidates must be aware of different stem modification and their functions.