Cyclitols and carbohydrates in leaves and roots of 13 Eucalyptus species suggest contrasting physiological responses to water deficit
Article first published online: 10 AUG 2006
Plant, Cell & Environment
Volume 29, Issue 11, pages 2017–2029, November 2006
How to Cite
MERCHANT, A., TAUSZ, M., ARNDT, S. K. and ADAMS, M. A. (2006), Cyclitols and carbohydrates in leaves and roots of 13 Eucalyptus species suggest contrasting physiological responses to water deficit. Plant, Cell & Environment, 29: 2017–2029. doi: 10.1111/j.1365-3040.2006.01577.x
- Issue published online: 10 AUG 2006
- Article first published online: 10 AUG 2006
- Received 22 March 2006, received in revised form 16 June 2006; accepted for publication 29 June 2006
- osmotic adjustment;
- water potential
In many tree species, physiological adaptations to drought include the accumulation of osmotically active substances and/or the presence of particular compatible solutes, among them cyclitols. Recently, the cyclitol quercitol was identified in species of Eucalyptus, a diverse genus whose speciation is probably driven by adaptation to water availability.
We subjected seedlings of 13 Eucalyptus species from different ecosystems (‘mesic’ and ‘xeric’) and different sub-generic taxonomic groups to 10 weeks of water deficit (WD) treatment. Pre-dawn water potentials (ψpdwn) and relative water content (RWC) were determined in shoots, and total osmolality, soluble low-molecular-weight carbohydrates and cyclitols were measured in leaves and roots.
Responses to water deficit followed two distinct patterns: Eucalyptus species from ‘mesic’ environments adjusted concentrations of sucrose (through increased levels of sucrose and decreases in RWC) in response to water deficit, whereas ‘xeric’ species increased concentrations of quercitol (through reductions in RWC). In root tissues, only species from xeric environments contained high levels of quercitol and mannitol, increasing under WD conditions.
We suggest that the former (mesic) strategy may be beneficial to respond to short-lasting drought conditions, because sucrose is easily metabolized, whereas the latter (xeric) strategy may relate to an effective acclimation to longer-lasting drought. These physiological response groups are also related to taxonomic groups within the genus.