Desert plants have adapted to perform photosynthesis in unique ways to survive the harsh, arid conditions. Primarily, they use a specialized process called Crassulacean Acid Metabolism (CAM).
Here's how CAM photosynthesis works in desert plants:
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Nocturnal CO2 Uptake: During the cooler night, desert plants open their stomata to take in carbon dioxide (CO2). This minimizes water loss, which is a critical adaptation in the desert environment.
- According to the provided reference, "In dessert plants the stomata are open at night. They take in CO2 at night."
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CO2 Storage: The absorbed CO2 is then converted into an intermediate compound, typically an acid, and stored within the plant's cells.
- The reference also states that the CO2 "is stored in the form of an intermediate (converted to an acid)".
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Daytime Photosynthesis: During the day, when sunlight is available for photosynthesis, the stomata remain closed to conserve water. The stored CO2 is released from the intermediate compound and used in the Calvin cycle to produce sugars.
- The provided reference highlights that the stored CO2 "is used during the day for photosynthesis,(when the stomata are closed)".
CAM Photosynthesis: A Summary
| Feature | Description | Advantage |
|---|---|---|
| Stomata Opening | Occurs at night | Minimizes water loss during the hottest part of the day. |
| CO2 Intake | Takes place at night | Allows plants to acquire carbon when temperatures are lower and humidity is higher. |
| CO2 Storage | CO2 is converted to and stored as an acid. | Provides a readily available source of CO2 for photosynthesis during the day. |
| Photosynthesis Time | Occurs during the day with stomata closed, utilizing stored CO2. | Allows photosynthesis to proceed even when stomata are closed, preventing further water loss. |
Example:
A common example of a CAM plant is the cactus. Cacti thrive in arid environments due to their ability to utilize CAM photosynthesis, allowing them to survive with minimal water loss.
In summary, desert plants have evolved CAM photosynthesis to separate the processes of carbon dioxide uptake and the Calvin cycle in time, allowing them to conserve water and survive in harsh desert conditions.
