The curvature in Avena coleoptile is associated with which growth substance

Options

A. IAA
B. gibberellins
C. kinetin
D. abscisic acid

Answer

**Step-by-Step Solution:**

1. **Identify the Subject of the Question**: The question asks about the curvature in Avena coleoptile and which growth substance is associated with it.

2. **Understand the Avena Coleoptile Experiment**: Avena coleoptile is a plant structure used in experiments to study phototropism (growth in response to light). The curvature observed in the coleoptile is a response to light, which is influenced by growth hormones.

3. **List the Growth Substances Mentioned**: The options provided in the question include:
- IAA (Indole-3-Acetic Acid)
- Zeberlin
- Kinetin
- Abscisic Acid

4. **Recall the Role of Auxins**: Auxins are a class of plant hormones that play a crucial role in the regulation of plant growth and are particularly known for their role in cell elongation and phototropism.

5. **Refer to the Experiment by F.W. Wendt**: F.W. Wendt conducted an experiment where he removed the tips of Avena coleoptiles and placed them on agar blocks. This allowed the growth substance (auxin) to diffuse into the agar.

6. **Analyze the Results of the Experiment**: When the agar blocks containing the diffused substance were placed on decapitated coleoptiles, it resulted in normal growth and curvature. This indicated that the substance responsible for the curvature was indeed auxin.

7. **Identify the Correct Answer**: Based on the information gathered, the growth substance associated with the curvature in Avena coleoptile is IAA (Indole-3-Acetic Acid), which is a type of auxin.

**Final Answer**: The curvature in Avena coleoptile is associated with IAA (Indole-3-Acetic Acid).

---