Which group of plants are not beefitted by `CO_(2)` fertilisation effect ?

Options

A. Plants requiring 3 ATP per ` CO_(2)` fixation
B. Plants with Kranz anatomy
C. Plants having high rate of photorespiration
D. Plants having single carboxylation

Answer

### Step-by-Step Solution:

1. **Understanding CO2 Fertilization Effect**:
- CO2 fertilization refers to the enhancement of plant growth due to increased levels of carbon dioxide (CO2) in the atmosphere. This effect is primarily beneficial for certain types of plants, particularly C3 plants.

2. **Identifying Plant Groups**:
- There are different groups of plants based on their photosynthetic pathways: C3 plants, C4 plants, and CAM plants.
- C3 plants do not have Kranz anatomy and are directly affected by increased CO2 levels, leading to enhanced photosynthesis and growth.

3. **C4 Plants and Kranz Anatomy**:
- C4 plants possess Kranz anatomy, which is an adaptation that allows them to efficiently fix CO2 even at lower concentrations.
- Due to this adaptation, C4 plants are less affected by the increase in CO2 levels because they have already evolved mechanisms to minimize photorespiration.

4. **Photorespiration**:
- Photorespiration is a process that occurs in plants when oxygen competes with CO2 for the active site of the enzyme RuBisCO, leading to a wasteful process that reduces photosynthetic efficiency.
- C3 plants are more susceptible to photorespiration, which is why they benefit from increased CO2 levels.

5. **Conclusion**:
- Given the information, the group of plants that does not benefit from CO2 fertilization is the **C4 plants**, which have Kranz anatomy and already utilize CO2 efficiently.

### Final Answer:
The group of plants that are not benefited by CO2 fertilization effect is **plants with Kranz anatomy (C4 plants)**.

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