For gaseous exchange plants have -

Options

A. Stomata
B. Lenticles
C. Porin
D. a and b

Answer

**Step-by-Step Solution:**

1. **Understanding Gaseous Exchange in Plants:**
- Plants primarily exchange gases such as carbon dioxide (CO2) and oxygen (O2) for processes like photosynthesis and respiration.

2. **Identifying Key Structures for Gaseous Exchange:**
- The main structures involved in gaseous exchange in plants are stomata, lenticels, and porins.

3. **Stomata:**
- Stomata are small openings found mainly on the epidermis of leaves, but they can also be present on green stems.
- They are surrounded by guard cells that regulate their opening and closing, allowing for the exchange of gases.

4. **Guard Cells:**
- In monocot plants, guard cells have a dumbbell shape, while in dicot plants, they are typically bean-shaped or kidney-shaped.
- The shape of guard cells is crucial for their function in regulating the size of the stomatal opening.

5. **Lenticels:**
- In woody plants, where the stems are not green, gas exchange occurs through structures called lenticels.
- Lenticels are small openings in the bark that allow for gas exchange even in non-living tissues.

6. **Porins:**
- Porins are proteins located in the plasma membrane of cells that facilitate the diffusion of molecules, including gases, across the membrane.
- They play a role in the movement of gases into and out of the plant cells.

7. **Conclusion:**
- In summary, plants utilize stomata, lenticels, and porins to effectively exchange gases necessary for their survival and metabolic processes.

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