Distribution of cell-wall xylans in bryophytes and tracheophytes: new insights into basal interrelationships of land plants
Article first published online: 16 JUN 2005
Volume 168, Issue 1, pages 231–240, October 2005
How to Cite
Carafa, A., Duckett, J. G., Knox, J. P. and Ligrone, R. (2005), Distribution of cell-wall xylans in bryophytes and tracheophytes: new insights into basal interrelationships of land plants. New Phytologist, 168: 231–240. doi: 10.1111/j.1469-8137.2005.01483.x
- Issue published online: 16 JUN 2005
- Article first published online: 16 JUN 2005
- Received: 1 April 2005 Accepted: 3 May 2005
- plant phylogeny;
- secondary cell walls;
- vascular tissues;
- • Xylans are known to be major cellulose-linking polysaccharides in secondary cell walls in higher plants.
- • We used two monoclonal antibodies (LM10 and LM11) for a comparative immunocytochemical analysis of tissue and cell distribution of xylans in a number of taxa representative of all major tracheophyte and bryophyte lineages.
- • The results show that xylans containing the epitopes recognized by LM10 and LM11 are ubiquitous components of secondary cell walls in vascular and mechanical tissues in all present-living tracheophytes. In contrast, among the three bryophyte lineages, LM11 binding was detected in specific cell-wall layers in pseudoelaters and spores in the sporophyte of hornworts, while no binding was observed with either antibody in the gametophyte or sporophyte of liverworts and mosses.
- • The ubiquitous occurrence of xylans containing LM10 and LM11 epitopes in tracheophytes suggests that the appearance of these polysaccharides has been a pivotal event for the evolution of highly efficient vascular and mechanical tissues. LM11 binding in the sporophyte of hornworts, indicating the presence of relatively highly substituted xylans (possibly arabinoxylans), separates these from the other bryophytes and is consistent with recent molecular data indicating a sister relationship of the hornworts with tracheophytes.