Are bananas C3, C4, or CAM plants?
First of all, we have to think about the ecosystem in which banana exist. Obviously, the banana is in a rain forest. Rain forests are a very interesting ecosystem with lots of species. The climate is really hot and the atmosphere has high humidity.



Banana is definitely not CAM plant, because this kind of photosynthesis has usually cactuses and succulents. CAM plants usually have closed stromas during the day and open at night to protect from possible loss of water, carbon dioxide. This type of photosynthesis doesn't suite into the rain forest.



C4 plants are well known for Kranz anatomy of a leaf. They have special sheets to do secondary fixation of carbon dioxide. So according to this web I personally believe that banana is not C4 plant.




So according to this article the banana has C3 photosynthesis.