Salt stress induces the formation of a novel type of ‘pressure wood’ in two Populus species
Article first published online: 29 NOV 2011
© 2011 The Authors. New Phytologist © 2011 New Phytologist Trust
Special Issue: Featured papers on ‘Bioenergy trees’
Volume 194, Issue 1, pages 129–141, April 2012
How to Cite
Janz, D., Lautner, S., Wildhagen, H., Behnke, K., Schnitzler, J.-P., Rennenberg, H., Fromm, J. and Polle, A. (2012), Salt stress induces the formation of a novel type of ‘pressure wood’ in two Populus species. New Phytologist, 194: 129–141. doi: 10.1111/j.1469-8137.2011.03975.x
- Issue published online: 24 FEB 2012
- Article first published online: 29 NOV 2011
- Received: 27 August 2011, Accepted: 14 October 2011
- arabinogalactan protein;
- fasciclin-like protein;
- salt transcriptome;
- •Salinity causes osmotic stress and limits biomass production of plants. The goal of this study was to investigate mechanisms underlying hydraulic adaptation to salinity.
- •Anatomical, ecophysiological and transcriptional responses to salinity were investigated in the xylem of a salt-sensitive (Populus × canescens) and a salt-tolerant species (Populus euphratica).
- •Moderate salt stress, which suppressed but did not abolish photosynthesis and radial growth in P. × canescens, resulted in hydraulic adaptation by increased vessel frequencies and decreased vessel lumina. Transcript abundances of a suite of genes (FLA, COB-like, BAM, XET, etc.) previously shown to be activated during tension wood formation, were collectively suppressed in developing xylem, whereas those for stress and defense-related genes increased. A subset of cell wall-related genes was also suppressed in salt-exposed P. euphratica, although this species largely excluded sodium and showed no anatomical alterations. Salt exposure influenced cell wall composition involving increases in the lignin : carbohydrate ratio in both species.
- •In conclusion, hydraulic stress adaptation involves cell wall modifications reciprocal to tension wood formation that result in the formation of a novel type of reaction wood in upright stems named ‘pressure wood’. Our data suggest that transcriptional co-regulation of a core set of genes determines reaction wood composition.