Contributors: SD and CD equally contributed to this study and are considered as co-first authors.
Mechanism of water-stress induced cavitation in conifers: bordered pit structure and function support the hypothesis of seal capillary-seeding
Article first published online: 12 NOV 2010
© 2010 Blackwell Publishing Ltd
Plant, Cell & Environment
Volume 33, Issue 12, pages 2101–2111, December 2010
How to Cite
DELZON, S., DOUTHE, C., SALA, A. and COCHARD, H. (2010), Mechanism of water-stress induced cavitation in conifers: bordered pit structure and function support the hypothesis of seal capillary-seeding. Plant, Cell & Environment, 33: 2101–2111. doi: 10.1111/j.1365-3040.2010.02208.x
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- Issue published online: 12 NOV 2010
- Article first published online: 12 NOV 2010
- Received 6 April 2010; received in revised form 2 July 2010; accepted for publication 5 July 2010
- bordered pit;
Resistance to water-stress induced cavitation is an important indicator of drought tolerance in woody species and is known to be intimately linked to the anatomy of the xylem. However, the actual mechanical properties of the pit membrane are not well known and the exact mode of air-seeding by which cavitation occurs is still uncertain. We examined the relationship between cavitation resistance and bordered pit structure and function in 40 coniferous species. Xylem pressure inducing 50% loss of hydraulic conductance (P50, a proxy for cavitation resistance) varied widely among species, from −2.9 to −11.3 MPa. The valve effect of the pit membrane, measured as a function of margo flexibility and torus overlap, explained more variation in cavitation-resistance than simple anatomical traits such as pit membrane, pit aperture or torus size. Highly cavitation resistant species exhibited both a high flexibility of the margo and a large overlap between the torus and the pit aperture, allowing the torus to tightly seal the pit aperture. Our results support the hypothesis of seal capillary-seeding as the most likely mode of air-seeding, and suggest that the adhesion of the torus to the pit border may be the main determinant of cavitation resistance in conifers.