Which of the following are arranged in acropetal order?

A. The leaves on a stem

B. The flowers of racemose inflorescence

C. The flowers of a cymose inflorescence

In botany, acropetal refers to the sequential arrangement where growth or development occurs from the base toward the apex, or from older to younger structures. This pattern is commonly observed in various plant structures. Let us analyze the question and explore examples of acropetal arrangement:

Explanation of the Options

1. The Leaves on a Stem: Leaves on a stem follow an acropetal arrangement. In this sequence, the older leaves are positioned at the base, while younger leaves develop progressively towards the apex.
2. The Flowers of Racemose Inflorescence: In racemose inflorescence, the flowers also exhibit an acropetal order. This means that the older flowers are located at the base of the inflorescence, and younger flowers are formed successively towards the tip.
3. The Flowers of a Cymose Inflorescence: In contrast to racemose, cymose inflorescence does not follow an acropetal pattern. Here, the growth is basipetal, where the oldest flowers are at the tip, and newer ones form below.

Additional Example

Apart from the above examples, lateral roots of a tap root system also follow an acropetal sequence. The older lateral roots are located near the base of the tap root, while newer lateral roots emerge towards the growing tip.

Final Answer

Structures arranged in an acropetal order include:

• The leaves on a stem
• The flowers of racemose inflorescence
• The lateral roots of a tap root system

Understanding the concept of acropetal arrangement is essential in botany as it highlights the developmental patterns in plants and helps distinguish between different types of growth and inflorescences.