Respiration in Plants
All living things need air to survive. All living things must breathe and respire.
Plants breathe by means of stomata. These are tiny pores found under the surface of leaves.
There are two important gases in the air are oxygen (O2) and carbon dioxide (CO2).
Our bodies can only absorb nutrients from sugary food. However, most of the foods we eat are starchy and fatty and our bodies cannot absorb nutrients from them. These foods must be changed to sugar. Oxygen is needed to do this. Therefore, when we breathe, we only use the oxygen and exhale the carbon dioxide.
In order to make plant food (starch) plants must use carbon dioxide. This means that during the day plants take in carbon dioxide and give off oxygen. Like over bodies plants too, cannot absorb the nutrients from the starchy plant food which was made or manufactured in the leaves. It must be changed to sugar. What is needed to change starch to sugar: (oxygen is needed). Therefore, plants take in oxygen at nights in order to change the starchy plant food to sugars.