Plants perform respiration like any other organism. So, it uses oxygen and food to produce energy and carbon dioxide.

However, plants also photosynthesize, meaning that it will convert carbon dioxide and water win the presence of light with the help of chlorophyll to produce oxygen and food. This is how plants get their sugars.

Now, since plants grow slower, do not need as much energy as animals, is requires less sugars and therefore respire less. Hence, the net effect is that they perform more photosynthesis than respiration.

Tick, I don't know what plants do with carbon monoxide, but since carbon monoxide quite readily reacts in air to form carbon dioxide, I don't think plants use them. However, more research might be done to confirm this.