This type of modification I seen inplants and it takes place via the stomata of the leave and through the lenticles found on young stems. During the day photosynthesis take place carbon dioxide and water are use up to produce carbohydrate and oxygen. The concentration of carbon dioxide drops because it is been use in photosynthesis. Water moves from the surrounding cells to guard resulting in the opening of the stomata. Gaseous exchange now take place. Oxygen which have a greater concentration on the cell diffuses out of the cell via the stomata, passing through air spaces in the mesophyll cell of the leave. Carbon dioxide which has a greater concentration outside also, diffuses into the cell through the same route.

      This is so because photosynthesis rate during the day is faster than respiration. The cells need more carbon dioxide during the day for photosynthesis as such water may be lost as water vapor resulting in a pooling effect.

      Plant growing in molting areas such as swamps e.g mangrove areas. They have special branches and roots known as neumutophores that grows upward through the mud into the air and this enable the root to breath in a water logged soil. The neumatophores which are spongy with many air spaces absorb air.