The most common type of tapetum is

Options

A. Secretary or glandular type
B. Amoeboid or invasive type
C. Nonglandular and noninvasive type
D. Resupinate type

Answer

**Step-by-Step Solution:**

1. **Understanding Tapetum:**
- The tapetum is a layer of cells in the anther of flowering plants that provides nourishment to developing pollen grains.

2. **Identifying Types of Tapetum:**
- There are different types of tapetum, including:
- Invasive (or Embryoid) Tapetum
- Amorphous Tapetum
- Cellular Tapetum

3. **Determining the Most Common Type:**
- Among these types, the invasive type of tapetum is the most common. This type is also referred to as the embryoid type and is known as the periplasmodium.

4. **Characteristics of Invasive Tapetum:**
- The invasive tapetum is characterized by the fusion of tapetal cells, forming a structure called the tapetal periplasmodium.
- This type of tapetum is commonly found in angiosperms, which are flowering plants.

5. **Examples of Plants with Invasive Tapetum:**
- The invasive tapetum can be observed in various plant species such as Adenosma, Typha, and Butomus.

6. **Function of the Tapetum:**
- The protoplasts of the fused tapetal cells can move into the locule (the cavity within the anther) during the meiotic prophase, contributing to the development of pollen grains.

7. **Conclusion:**
- Therefore, the most common type of tapetum is the invasive type, also known as the embryoid or periplasmodial tapetum.

**Final Answer:**
- The most common type of tapetum is the invasive type (embryoid type or periplasmodium).

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