Which of the following is a plant growth inhibiter?

Options

A. Heteroauxin
B. Gibberrellins
C. Cytokinnis
D. Abscisic acid `(ABA)`

Answer

To determine which of the following is a plant growth inhibitor, we need to analyze the options provided:

1. **Heteroauxin**: This is a type of auxin, which is a plant hormone that promotes growth, particularly in stem elongation and root formation. Therefore, it is not a growth inhibitor.

2. **Gibberellin**: This hormone is known for promoting growth, particularly in seed germination and stem elongation. Like heteroauxin, gibberellin is not a growth inhibitor.

3. **Cytokinin**: This hormone promotes cell division and growth in plants. It is involved in various growth processes, including shoot development and leaf expansion. Thus, cytokinin is also not a growth inhibitor.

4. **Abscisic Acid (ABA)**: This hormone is known to inhibit growth and is involved in processes such as seed dormancy and the response to stress conditions (like drought). It acts antagonistically to growth-promoting hormones.

Based on this analysis, the correct answer to the question "Which of the following is a plant growth inhibitor?" is:

**Option D: Abscisic Acid.**