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Xylem Function and Evolution

A project contributing to the understanding of secondary xylem evolution in woody plants, including ecological adaptations and physiological functions in extant wood.
Dr. Yuzou Sano conducting a dye-injection experiment to visualise water distribution pathways in Sorbus commixta Hedl. (Rosaceae) at the Sapporo Experimental Nursery of Hokkaido University (Japan). © Steven Jansen

This project aims to contribute to our understanding of xylem evolution in woody plants and of ecological adaptations and physiological functions in extant wood. Although in many cases wood anatomical diversity patterns reflect their phylogenetic significance, there is a considerable amount of convergence, which can partly be interpreted as the result of ecological adaptations for water transport and mechanical support. Ecological trends in turn can be understood as adaptive trade-offs between structure and function in different growth forms and environments, especially with respect to conductive efficiency, resistance to embolism, and mechanical strength.

Special attention is paid to the structure and function of pits and pit membranes. Given the large variation of pit characteristics, these features pose questions with respect to their convergent nature and functional significance. Pits affect the movement of sap in living trees, and also the penetration of liquids, preservatives and gases in timber, so research on pit characters also contributes to applications in wood technology, including the paper and pulp industry.

This project is in collaboration with project partners from diverse research fields, including plant phylogeny, systematic wood anatomy, ecology, xylem physiology, and biomechanics and palaeobotany. Output consists of peer-reviewed scientific publications in general scientific journals as well as in leading subject journals (subject areas Plant Anatomy, Plant Physiological Ecology, Tree Physiology, Plant Systematics), presentations at international meetings, and collaboration with overseas colleagues through joint research.

Key publications 2006-2011

  • Rabaey, D., Lens, F., Smets, E. & Jansen, S. (2010). The phylogenetic significance of vestured pits in Boraginaceae. Taxon 59: 510-516.
  • Oakley, D, Falcon-Lang, H.J. & Gasson, P. (2009). Morphometric analysis of some Cretaceous angiosperm woods and their extant structural and phylogenetic analogues: implications for systematics. Review of Palaeobotany and Palynology 157: 375-390.
  • Chave, J., Coomes, D., Jansen, S., Lewis, S.L., Swenson, N.G. & Zanne, A. (2009). Towards a worldwide wood economics spectrum. Ecology Letters 12: 351-366.
  • Choat, B., Cobb, A.R. & Jansen, S. (2008). Structure and function of bordered pits: new discoveries and impacts on whole-plant hydraulic function. New Phytologist 177: 608-625.
  • Jansen, S., Sano, Y., Choat, B., Rabaey, D., Lens, F. & Dute, R.R. (2007). Pit membranes in imperforate tracheary elements of Rosaceae and related families: new records of tori and pseudo-tori. American Journal of Botany 94: 503-514.
  • Rabaey, D., Lens, F., Smets, E. & Jansen, S. (2006). The micromorphology of pit membranes in tracheary elements of Ericales: new records of tori or pseudo-tori? Annals of Botany 98: 943-951.


Project partners and collaborators


Bordeaux University (Sylvain Delzon)


Ulm University (Steven Jansen)


Royal Holloway College (Howard Falcon-Lang)

Project Department

Project Leader: