Which of the following is incorrect about plant hormones?

Options

A. They influence plant growth and development at low concentrations.
B. Abscisic acid is growth retarding hormone
C. They are organic compounds.
D. Ethylene decreases the respiration rate in fruits.

Answer

To determine which statement about plant hormones is incorrect, let's analyze each of the four statements provided:

1. **Statement 1**: "They influence plant growth and development at low concentrations."
- **Analysis**: This statement is true. Plant hormones, also known as plant growth regulators (PGRs), are effective in very low concentrations and play a crucial role in regulating various aspects of growth and development in plants.

2. **Statement 2**: "Abscisic acid is a growth retarding hormone."
- **Analysis**: This statement is also true. Abscisic acid (ABA) is known to inhibit growth and is involved in processes such as stomatal closure and promoting seed dormancy, making it a growth-retarding hormone.

3. **Statement 3**: "They are organic compounds."
- **Analysis**: This statement is correct as well. Plant hormones are indeed organic compounds that are produced naturally within the plant.

4. **Statement 4**: "Ethylene decreases the respiration rate in fruits."
- **Analysis**: This statement is incorrect. Ethylene is a plant hormone that actually increases the respiration rate in fruits and is involved in the ripening process. It promotes the conversion of starches to sugars, leading to the ripening of fruits.

Based on the analysis, the incorrect statement about plant hormones is:

**Answer**: Ethylene decreases the respiration rate in fruits (Statement 4).

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