Abstract
Gas through-flow by pressurised ventilation is well known in floating-leaved aquatic plants. The ventilation system operates via different structural features in different species: being through rhizomes in Nuphar species, is restricted to whorls in Nymphoides, or even individual leaves in Nelumbo. The convective through-flow in these aquatic plants is the result of a gas-pumping system, commonly powered by solar radiation, with air influx and pressurisation of the youngest, just emerged leaves along positive humidity and temperature gradients between leaf aerenchyma and the ambient atmosphere. It improves the internal aeration of submerged plant organs, has high physiological significance to the plant, and confers beneficial effects on the ecosystem. Since the acquisition of gas through-flow systems is not restricted to closely related plant species, but can be correlated with special ecosystemal conditions, it should be seen as a special adaptation to plant survival under oxygen shortage stress.