Which of the following may be the substitute of photoperiodism?

Options

A. Humidity
B. Temperature
C. Mineral nutrients
D. Soil moisture

Answer

**Step-by-Step Solution:**

1. **Understanding Photoperiodism**: Photoperiodism is the physiological reaction of organisms to the length of day or night. In plants, it primarily influences flowering and growth.

2. **Historical Context**: Photoperiodism was first studied by W.W. Garner and H.A. Allard in 1906, particularly in the Tobacco plant. They categorized plants based on their response to daylight into three groups: long-day plants, short-day plants, and day-neutral plants.

3. **Factors Influencing Flowering**: The primary factor that influences flowering in plants is the photoperiod, which is the duration of light exposure. However, there are other factors that can also induce flowering.

4. **Substitutes for Photoperiodism**: One of the key substitutes for photoperiodism is temperature. Specifically, the process of lowering temperature can induce flowering in certain plants.

5. **Vernalization**: This process of inducing flowering through low temperatures is known as vernalization. It involves exposing plants to prolonged cold conditions, which can trigger flowering regardless of the photoperiod.

6. **Conclusion**: Therefore, the substitute for photoperiodism, in terms of inducing flowering, is temperature, particularly through the process of vernalization.

**Final Answer**: The substitute of photoperiodism may be temperature (through vernalization).

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