Record rates of pressurized gas-flow in the great horsetail, Equisetum telmateia. Were Carboniferous Calamites similarly aerated?
Article first published online: 12 JUN 2009
© The Authors (2009). Journal compilation © New Phytologist (2009)
Volume 184, Issue 1, pages 202–215, October 2009
How to Cite
Armstrong, J. and Armstrong, W. (2009), Record rates of pressurized gas-flow in the great horsetail, Equisetum telmateia. Were Carboniferous Calamites similarly aerated?. New Phytologist, 184: 202–215. doi: 10.1111/j.1469-8137.2009.02907.x
- Issue published online: 2 SEP 2009
- Article first published online: 12 JUN 2009
- Received: 1 March 2009Accepted: 20 April 2009
- Carboniferous Calamites;
- Equisetum telmateia;
- humidity-induced convective aeration;
- mathematical modelling;
- • Significant pressurized (convective) ventilation has been demonstrated in some flowering wetland plants, for example water-lilies and reeds, but not previously in nonflowering plants. Here we investigated convective flows in the great horsetail, Equisetum telmateia, and the possibility that convections aerated the massive rhizomes of the Calamites, extinct giant horsetails of the Carboniferous.
- • Convection in E. telmateia was examined in relation to induction sites, anatomical pathways, relative humidity (RH), external wind-speed, diurnal effects, rhizome resistance and pressure-gradients. A mathematical model, incorporating Calamite aeration anatomy, was applied in assessing potentials for convective aeration.
- • Individual shoots of E. telmateia generated extremely high rates of humidity-induced convection: ≤ 120 cm3 min−1 (internal wind-velocity: 10 cm s−1) with rates proportional to branch numbers and 1/RH. Flows passed through branches, stem and rhizome via low-resistance lacunae (vallecular canals) and vented via stubble. Stomata supported internal pressures up to 800 Pa. Anatomically, E. telmateia resembles the Calamites and modelling predicted possible flows of 70 l min−1 per Calamite tree.
- • This is the first demonstration of significant convective flow in a nonflowering species, indicating that plant ventilation by a type of ‘molecular gas-pump’ may date back 350 million yr or more. Stomatal form and low-resistance pathways may facilitate high flow rates.