The spongy tissues of the mesophyll cells are with greater inter cellular space. Large internal exposed cell surface which facilitate gaseous and water vapour exchange between cells and intercellular air spaces. This inters ventilating system opens through the stomata on the lower epidermis. Below the stomatal pore there is the presence of respiratory chamber. This chamber collects the gas and the vapour from the inter cellular space from there it escapes out. Similarly the air and CO2 from outside enters the stomata and gets collected in the stomatal chamber and from this chamber the gas gets distributed among the mesophyll cells.