A.T.S. of dithecous anther shows

Options

A. endothecium inner to middle layers
B. tapetum just below endothecium
C. middle layers between endothecium and tapetum
D. tapetum below epidermis

Answer

### Step-by-Step Solution:

1. **Understanding Diethycus Anther**:
- A diethycus anther is characterized by having two lobes (or thecae) and is tetrasporangiate, meaning it contains four sporangia.

2. **Identifying Layers of the Anther**:
- The anther consists of several layers:
- **Epidermis**: This is the outermost layer of the anther.
- **Endothelium**: Located just beneath the epidermis, this layer plays a role in the dehiscence of the anther.
- **Middle Layer**: This layer is found between the endothelium and the tapetum. It typically consists of a few layers of cells that provide nourishment.
- **Tapetum**: This is a multinucleated layer that is crucial for the development of pollen grains. It lies just below the middle layer.
- **Sporogenous Tissue**: This is the innermost layer where pollen grains are produced.

3. **Correct Arrangement of Layers**:
- The correct order of the layers from outermost to innermost is:
- Epidermis
- Endothelium
- Middle Layer
- Tapetum
- Sporogenous Tissue

4. **Analyzing the Options**:
- Based on the arrangement of the layers:
- **Endothelium is inner to the middle layer**: This is incorrect; the endothelium is outer to the middle layer.
- **Tapetum just below the endothelium**: This is also incorrect; the middle layer is present between the endothelium and the tapetum.
- **Middle layer is between endothelium and tapetum**: This is correct.
- **Tapetum is below the epidermis**: This is incorrect; the tapetum is below the middle layer, not directly below the epidermis.

5. **Conclusion**:
- The correct statement regarding the arrangement of layers in a diethycus anther is that the middle layer is located between the endothelium and the tapetum.