Yes, it is true that peepal trees can release CO2 at night. Unlike most other plants that perform a type of photosynthesis called C3, peepal trees use a different pathway known as Crassulacean Acid Metabolism (CAM). This type of photosynthesis allows peepal trees to take up carbon dioxide during the night, when they keep their stomata open, and store it as malic acid in their cells. During the day, when sunlight is available, peepal trees close their stomata to reduce water loss through transpiration and convert the stored malic acid back into carbon dioxide for photosynthesis.
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CAM plants, such as peepal trees, have evolved this unique mechanism to cope with hot and dry climates. By taking up carbon dioxide during the night when temperatures are lower and stomatal openings result in less water loss, peepal trees are able to maximize their carbon dioxide uptake while minimizing water loss. This adaptation enables them to survive in arid and semi-arid conditions.
Therefore, peepal trees do release CO2 at night, as part of their CAM photosynthesis process. This ability to perform photosynthesis during both day and night is a significant advantage for peepal trees, as it allows them to continue their carbon dioxide uptake and provide environmental benefits, even when there is no sunlight available for traditional photosynthesis.