In which of the following the pollen tube enters via chalaza ?

Options

A. Ottelia
B. Casuarina
C. Cucurbita
D. Both ( A) and ( C)

Answer

To solve the question "In which of the following the pollen tube enters via chalaza?", we need to understand the different ways pollen tubes can enter the ovule during fertilization. Here’s a step-by-step breakdown:

### Step 1: Understand the Terms
- **Pollen Tube**: A tube that forms after pollen germinates and carries male gametes to the ovule.
- **Chalaza**: The basal part of the ovule where the integuments are attached.
- **Micropyle**: The opening in the ovule through which the pollen tube usually enters, commonly seen in most plants.

### Step 2: Identify the Types of Gametophyte Entry
- **Porogamy**: The pollen tube enters through the micropyle (most common method).
- **Chalazogamy**: The pollen tube enters through the chalaza (less common).
- **Mesogamy**: The pollen tube enters through the middle region of the ovule (rare).

### Step 3: Analyze the Given Options
- **Otelia**: Not commonly known for chalazogamy.
- **Casuarina**: Known for chalazogamy, where the pollen tube enters through the chalaza.
- **Cucurbita**: Typically exhibits mesogamy, where the pollen tube enters through the middle.
- **Both A and C**: This option is incorrect as neither Otelia nor Cucurbita is known for chalazogamy.

### Step 4: Conclusion
Based on the definitions and examples:
- The correct answer is **Casuarina**, as it is the plant where the pollen tube enters via the chalaza.

### Final Answer
The pollen tube enters via chalaza in **Casuarina**.

---