Question

How many of the given plants show phyllotaxy, where a single leaf arises at each node?
Alstonia, Brassica, Calotropis, Chilli, China rose, Guava, Datura, Sunflower
A. Three
B. Five
C. Four
D. Six

Answer 1

Hint: One of the most significant elements of the plant is the leaves. The morphology and arrangement of leaves on the plant is a whole topic in itself. The arrangement of leaves on a plant stem is known as phyllotaxis or phyllotaxy in botany. On a stem, the basic leaf arrangements are opposite and alternate (also known as a spiral).

Complete answer:
Option A:
Phyllotaxy is shown by all the plants given. But the question says a type of phyllotaxy where a single leaf arises from each node. This only occurs in an alternate type of phyllotaxy. The alternate category of phyllotaxy exists in china rose, guava, sunflower and Datura. So, the examples here are more than three.
Hence, option A is incorrect.
Option B:
Many of the plants display phyllotaxy. The query, however, refers to a form of phyllotaxy in which a single leaf emerges from each node. This is only seen in a certain form of phyllotaxy. From the plants given, a total of five plants do not show the phyllotaxy referred to in the question.
Hence, option B is incorrect.
Option C:
China rose, mustard, sunflower plants, chilli, and Datura are examples of alternate phyllotaxy, in which a single leaf emerges alternately at each node. In the opposite type, as in Calotropis and guava plants, a pair of leaves emerges at each node and lies opposite each other. It's called Whorled when more than two leaves emerge from a node and form a whorl, as in Alstonia (also Brassica).
As a result, option C is correct.
Option D:
Phyllotaxy is seen in many of the plants. The question, on the other hand, is about a form of phyllotaxy in which only one leaf emerges from each node. This only occurs in a specific form of phyllotaxy. A total of 6 plants in the sample do not exhibit the phyllotaxy mentioned in the query.
Hence, option D is incorrect.

Hence, Option C is the correct answer.

Note:
If multiple leaves tend to emerge from the same level (at the same node) on a stem, they are said to be whorled. Two leaves emerge from the stem at the same stage (at the same node) on opposite sides of the stem in an opposite leaf arrangement. A whorl of two leaves can be thought of as an opposite leaf pair.