The spongy mesophyll contains very few chloroplasts and it has a large surface area in order to increase the diffusion of carbon dioxide and oxygen. There is an intercellular air space within the spongy mesophyll layer which also allows the diffusion of carbon dioxide and oxygen. The air spaces are connected to the stomata. Stomata is a porelike opening in the underside of the leaf that allows carbon dioxide and oxygen to diffuse into and out of the leaf.
