There are many importances of air in plants, such as: Plants need oxygen for respiration, oxygen is used to produce ATP, which is then utilised to carry out various functions in plants Carbon dioxide is used by plants to carry out photosynthesis. In plants, each part takes care of its need for gaseous exchange. As leaves have stomata for gaseous exchange, stems have lenticels.The plant uses different microbes for nitrogen fixation.Then this fixed nitrogen is used to make different amino acids and proteins.