Innermost microsporangial wall layer that nourishes pollen grains is

Options

A. Endothecium
B. Tapetum
C. Endodermis
D. Sporogenous tissue.

Answer

To solve the question regarding the innermost microsporangial wall layer that nourishes pollen grains, we can break down the information step by step:

### Step 1: Understand the Structure of Microsporangium
The microsporangium, which is part of the anther in flowering plants, has several layers in its wall. These layers include:
- Epidermis
- Endothesium
- Middle layers
- Tapetum

### Step 2: Identify the Layers
Among these layers, the innermost layer is the tapetum. The tapetum is crucial as it surrounds the sporogenous tissue, which is responsible for producing microspores.

### Step 3: Function of the Tapetum
The tapetum plays a vital role in nourishing the developing pollen grains. It provides the necessary nutrients and support for the microspores as they develop into pollen grains.

### Step 4: Analyze the Options
The options provided are:
- Endothesium
- Tapetum
- Endodermis
- Porogenous tissue

From our understanding:
- **Endothesium** is the second layer and does not nourish pollen grains.
- **Endodermis** is not part of the microsporangial wall.
- **Porogenous tissue** is not relevant in this context.

### Step 5: Conclusion
The correct answer to the question is **Tapetum**, as it is the innermost microsporangial wall layer that nourishes the pollen grains.

### Final Answer:
The innermost microsporangial wall layer that nourishes pollen grains is **Tapetum**.

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