Pathways of aeration and the mechanisms and beneficial effects of humidity- and Venturi-induced convections in Phragmites australis (Cav) Trin ex Steud

The pathways of diffusive, humidity- and Venturi-induced convective ventilations in Phragmites australis (Cav.) Trin. ex Steud., and the mechanisms of the convections are described. Experimental evidence, indicating those factors, e.g. low relative humidity (RH), light, large leaf-sheath area, which increase humidity-induced convection; and those which increase Venturi convections, e.g. high wind speed, are reviewed. The superior aerating effects of convective as opposed to diffusive ventilation within the plant and their influence on the rhizosphere are demonstrated experimentally and by mathematical modelling.