Quantitative or qualitative flowering depends upon low temperature . This phenomenon is called

Options

A. Photoperiodism
B. Vernalisation
C. Dormancy
D. Abscission

Answer

To solve the question regarding the phenomenon where quantitative or qualitative flowering depends upon low temperature, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks about a phenomenon where flowering in certain plants is influenced by low temperatures. This indicates a specific biological process.

2. **Identifying Key Terms**: The terms "quantitative" and "qualitative flowering" suggest that the amount and quality of flowering are affected by environmental conditions, specifically temperature.

3. **Exploring Related Concepts**: In plant biology, there are several processes that influence flowering, such as photoperiodism (light duration) and vernalization (temperature).

4. **Defining Vernalization**: Vernalization is the process by which certain plants require a period of cold temperatures to trigger flowering. This is crucial for plants that need to ensure they flower at the right time of year.

5. **Temperature Range for Vernalization**: The optimal temperature range for vernalization is typically between 3 to 17 degrees Celsius, with an average around 5 degrees Celsius. This low temperature helps prevent premature flowering.

6. **Examples of Vernalization**: Certain crops like wheat, barley, and rye exhibit vernalization. Biennial plants, such as sugar beets, carrots, and cabbages, also rely on this process, where they grow vegetatively in the first year and flower in the second.

7. **Conclusion**: Based on the understanding of vernalization and its role in flowering, we can conclude that the correct answer to the question is "vernalization."

### Final Answer:
The phenomenon where quantitative or qualitative flowering depends upon low temperature is called **vernalization**.

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