Anthesis refers to:

Options

A. Growth of pollen tube inside the carpel
B. Dehiscence of anthers
C. Opening of floral bud
D. Emergence of anthers.

Answer

**Step-by-Step Solution:**

1. **Understanding Anthesis**: Anthesis is a biological term that refers to a specific phase in the life cycle of a flower. It is the process during which a flower bud opens and becomes a fully developed flower.

2. **Timing of Anthesis**: Anthesis can occur at different times of the day. Flowers that open during the daytime are referred to as having diurnal anthesis, while those that open at night are referred to as having nocturnal anthesis.

3. **Characteristics of Flowers**:
- **Diurnal Anthesis**: Flowers that bloom during the day tend to be bright in color. This is an adaptation to attract pollinators that are active during daylight hours.
- **Nocturnal Anthesis**: Flowers that bloom at night often have faded or less vibrant colors. This adaptation may attract nocturnal pollinators, such as moths.

4. **Conclusion**: Therefore, the definition of anthesis is the opening of a flower bud, which can occur either during the day or at night.

**Final Answer**: Anthesis refers to the opening of a flower bud.

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