For flowering, critical dark period should always be exceeded in

Options

A. Long day plant
B. Short day plants
C. Day neutral plants
D. All type of plants

Answer

To solve the question "For flowering, critical dark period should always be exceeded in," we need to analyze the types of plants based on their light requirements for flowering.

### Step-by-Step Solution:

1. **Understanding Plant Types**:
- **Long Day Plants**: These plants require a longer duration of light (day length) than a certain critical length to flower. They typically bloom in late spring or early summer when days are longer.
- **Short Day Plants**: These plants require a shorter duration of light and a longer duration of uninterrupted darkness (critical dark period) to flower. They bloom in late summer or fall when days are shorter.
- **Day Neutral Plants**: These plants do not depend on the length of day or night for flowering. They can flower regardless of the light duration.

2. **Identifying the Critical Dark Period**:
- The critical dark period is the minimum duration of darkness that a plant needs to initiate flowering. For short day plants, this period must be exceeded for the plant to flower.

3. **Analyzing the Options**:
- **Option 1: Long Day Plant** - Incorrect, as these require longer light periods.
- **Option 2: Short Day Plant** - Correct, as these need the critical dark period to be exceeded for flowering.
- **Option 3: Day Neutral Plant** - Incorrect, as these do not rely on light duration.
- **Option 4: All Types of Plants** - Incorrect, as not all plants require a critical dark period for flowering.

4. **Conclusion**:
- The correct answer is **Short Day Plant**. For flowering, the critical dark period should always be exceeded in short day plants.

### Final Answer:
For flowering, the critical dark period should always be exceeded in **short day plants**.

---