Question

The leaf arises at the __________ on the stem.
A. Internode
B. Axil
C. Node
D. Petiole

Answer 1

Hint: It is also called the point of attachment of leaves. The stem has some distinct morphological features that help us to distinguish it from roots like the presence of nodes and internodes, multicellular hair, and positively phototropic nature.

Complete answer:Leaf on the other hand is a lateral outgrowth of a step that develops exogenously at the node. The internode is a portion of the stem between two nodes.
1. In some modifications of the stem, it is seen that roots also arise from nodes to spread and vegetative propagation.
2. When we see phyllotaxy of leaves, there are three types of the pattern or arrangement of leaves on stem or branch: alternate, opposite and whorled.
3. In an alternate type of phyllotaxy, one leaf arises at each node in an alternate manner. Example: Sunflower, Mustard, China rose, etc.
4. In the opposite phyllotaxy, a pair of leaves arise at each node and lie opposite to each other. Examples of the opposite type are the Guava plant and Calotropis.
5. In the whorled type of phyllotaxy, more than two leaves arise from the node and form a whorl. Example: Alstonia.

The correct answer is (C) Node.

Note: The axil is an angle between the upper surface of the leaf and the node from which it arises. When a bud arises at the axil it is called an axillary bud.
This axillary bud later develops into a branch.
A typical leaf consists of a leaf base, petiole, and lamina.
The petiole is a thin flexible part that holds the blade in light and allows it to flutter in wind and thereby cooling the leaf.