in dosiventral leaves

Options

A. upper surface is dark green as compared to lower surface
B. both the surface are equally green
C. lower surface is dark green
D. both the surfaces are dark green.

Answer

### Step-by-Step Solution:

1. **Understanding Dorsiventral Leaves**:
- Dorsiventral leaves are characterized by having two distinct surfaces: the upper (adaxial) surface and the lower (abaxial) surface. These surfaces are differentiated in terms of structure and function.

2. **Identifying the Surfaces**:
- The upper surface of a dorsiventral leaf is known as the upper epidermis, while the lower surface is referred to as the lower epidermis.

3. **Structure of the Upper Epidermis**:
- The upper epidermis is typically composed of palisade parenchyma. This type of tissue is tightly packed and contains chloroplasts, which are essential for photosynthesis. The presence of chloroplasts gives the upper surface a dark green color.

4. **Structure of the Lower Epidermis**:
- The lower epidermis consists of spongy parenchyma. This tissue is more loosely arranged, allowing for gas exchange and the diffusion of carbon dioxide. The lower surface is generally lighter in color compared to the upper surface due to the less dense arrangement of chloroplasts.

5. **Color Difference**:
- Due to the differences in the types of parenchyma present, the upper epidermis appears dark green (due to palisade parenchyma), while the lower epidermis appears light green (due to spongy parenchyma).

6. **Conclusion**:
- Therefore, in dorsiventral leaves, the upper surface is dark green compared to the lighter green lower surface, which is a key identifying feature of these leaves.