Folia Geobotanica

, Volume 31, Issue 1, pp 25–36

Pressurised aeration in wetland macrophytes: Some theoretical aspects of humidity-induced convection and thermal transpiration


  • William Armstrong
    • Department of Applied BiologyUniversity of Hull
  • Jean Armstrong
    • Department of Applied BiologyUniversity of Hull
  • Peter M. Beckett
    • Department of Applied MathematicsUniversity of Hull

DOI: 10.1007/BF02803991

Cite this article as:
Armstrong, W., Armstrong, J. & Beckett, P.M. Folia Geobot (1996) 31: 25. doi:10.1007/BF02803991


The pressurised gas-flows, humidity-induced convection (HIC) and thermal transpiration (TT), which are important for aeration and for greenhouse gas emissions in some wetland macrophytes, are described and discussed. Results obtained from simple mathematical modelling of the processes are presented to illustrate some of their more relevant features. It is emphasised that both processes require the presence of a micro-porous partition having a significantly greater resistance to pressure flow than to diffusion. In particular it is shown that whilst the potential to pressurise by these processes is inversely related to the pore diameters of the partition, the maximum gas flows are generated where pore diameters range from 0.1 to 0.2 μm. Where partitions are a surface feature (e.g. emergent macrophytes) a dominant role for HIC is predicted; where partitions are an embedded feature (e.g. water-lilies) it is deduced that HIC will still play a significant role, but the contribution of TT could be greater.



Copyright information

© Institute of Botany, Academy of Sciences of the Czech Republic 1996