How Do Plants Breathe?
The lungs of a plant, or what the plant breathes with corresponding to our lungs, are located in the leaves of the plant. Under a magnifying glass we can see the lungs of the leaf quite clearly. In addition to this we know that plants breathe, because if we put them in a vacuum where there is no air they die very quickly. The plant needs air or it will suffocate just as any animal will suffocate under similar conditions. Plants, however, do not make use of the oxygen as they find it in the air. They live on the carbon which they find in the air mixed with oxygen. What happens then is this. The plants take in through their lungs in the leaves carbonic acid gas from which they take the carbon and use it as food, and throw off the oxygen which they cannot use. Human beings and other animals take the oxygen into their lungs and use it and expel carbonic acid gas. The result is that each kind of life is dependent upon the other. If it were not for the plant life, men and other animals would find it difficult perhaps to find sufficient oxygen in the air to keep them alive, and if it were not for the carbonic acid gas which the animals throw off, plants and other vegetable life would have great difficulty in finding sufficient carbonic acid gas to go around.