The main difference between C3, C4, and CAM plants Is that C3 plants perform photosynthesis directly, C4 plants have an additional carbon fixation pathway, and CAM plants have a temporal separation of carbon fixation.
What are C3 plants?
C3 plants are a type of photosynthetic plants that use the C3 carbon fixation pathway. They include the majority of plant species on Earth. C3 plants initially fix carbon dioxide (CO2) into a three-carbon compound during photosynthesis.
However, they are generally less efficient in water usage and photosynthetic productivity than C4 and CAM plants.
What are C4 plants?
C4 plants are a type of photosynthetic plants that have adapted a specialized mechanism to enhance carbon fixation. They utilize a pathway called the C4 pathway, which enables them to capture and store carbon dioxide efficiently.
This adaptation allows C4 plants to thrive in environments with high temperatures and limited water availability.
What are CAM plants?
CAM (Crassulacean Acid Metabolism) plants are unique plants that have adapted to arid environments. They have a specialized photosynthetic pathway that allows them to conserve water. During the night, CAM plants open their stomata to take in carbon dioxide and store it as an organic acid.
During the day, when the stomata are closed to reduce water loss, they use the stored carbon dioxide to perform photosynthesis. This efficient water-saving strategy enables CAM plants to thrive in dry conditions.
C3 vs C4 vs CAM plants
The primary difference between C3, C4, and CAM plants are given below:
| Feature | C3 Plants | C4 Plants | CAM Plants |
| Leaf Anatomy | Normal mesophyll cells | Kranz anatomy (bundle sheath) | Kranz anatomy (bundle sheath) |
| CO2 Fixation | Calvin cycle | Calvin cycle + Hatch-Slack | Crassulacean acid metabolism |
| Photosynthetic Rate | Moderate | High | Low |
| Efficiency | Lower efficiency | Higher efficiency | Moderate efficiency |
| Response to Heat | Susceptible to high temperatures | Tolerant of high temperatures | Tolerant of high temperatures |
| Response to Drought | Susceptible to drought | Tolerant of drought | Tolerant of drought |
| Location | Majority of plants | Tropical and subtropical | Arid and desert environments |
| Examples | Wheat, rice, soybeans | Corn,E5D8E5garcane, sorghum | Cacti, succulents, pineapple |