Select the incorrect statement about photoperiodism.

Options

A. The site of perception of light / dark duration are the leaves.
B. Flowering in certain plants depends not only on a combination of light and dark exposures but also their relative durations.
C. The hypothesised hormonal substance migrates from shoot apices to leaves for inducing flowering .
D. Shoot apices modify themselves into flowering apices prior to flowering .

Answer

To solve the question of selecting the incorrect statement about photoperiodism, we can analyze each option provided in the question step by step.

### Step 1: Analyze Option A
**Statement:** "The site for perception of light and dark duration are the leaves."
- **Explanation:** This statement is correct. In plants, the leaves are the primary sites where light is perceived. They contain photoreceptors that detect the duration of light and darkness, which is crucial for photoperiodism.

### Step 2: Analyze Option B
**Statement:** "Flowers in a certain plant depend not only on the combination of light and dark exposure but also their relative duration."
- **Explanation:** This statement is also correct. Photoperiodism involves the response of plants to the relative lengths of day and night. Some plants are classified as long-day plants or short-day plants based on their flowering response to the duration of light and darkness.

### Step 3: Analyze Option C
**Statement:** "The hypothesis hormonal substance migrate from suit apices to the leaves for the inducing flowering."
- **Explanation:** This statement is incorrect. The correct process is that hormonal substances (such as florigen) migrate from the leaves to the shoot apices to induce flowering. The statement incorrectly states the direction of hormone migration.

### Step 4: Analyze Option D
**Statement:** "The shoot apices modify themselves into the flowering apices prior to the flowering."
- **Explanation:** This statement is correct. Before flowering occurs, the shoot apices undergo modifications to become flowering apices, which is a normal part of the flowering process.

### Conclusion
After analyzing all the options, we find that **Option C** is the incorrect statement about photoperiodism.

### Final Answer
**The incorrect statement about photoperiodism is Option C.**

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