ABSTRACT
Plants are important in regulating biogeochemical cycles in wetlands. Development of aerenchyma and related internal pathways for oxygen diffusion to roots is a major adaptation mechanism in wetland plants. Oxygen diffusion in wetland plants is regulated primarily by the volume of intercellular airspaces and the degree of space continuity. The capacity of wetland plants to survive under anaerobic soil conditions is largely dependent on the rate of plant respiration the rate of oxygen supply from photosynthetic tissue to below-ground roots. Perhaps the most significant long-term adaptation of wetland species to soil anaerobiosis is the development of the tissues and mechanisms to transport external gas into the soil from the atmosphere. Mass flow of gases in intercellular airspaces of wetland plants can be generated by several processes: thermal transpiration, humidity-induced diffusion, solubilization of respiratory carbon dioxide, and venturi effects across broken culms.
