Cyclitols and carbohydrates in leaves and roots of 13 Eucalyptus species suggest contrasting physiological responses to water deficit.

摘要: In many tree species, physiological adaptations to drought include the accumulation of osmotically active substances and/or presence particular compatible solutes, among them cyclitols. Recently, cyclitol quercitol was identified in species Eucalyptus, a diverse genus whose speciation is probably driven by adaptation water availability. We subjected seedlings 13 Eucalyptus from different ecosystems ('mesic' and 'xeric') sub-generic taxonomic groups 10 weeks deficit (WD) treatment. Pre-dawn potentials (psi(pdwn)) relative content (RWC) were determined shoots, total osmolality, soluble low-molecular-weight carbohydrates cyclitols measured leaves roots. Responses followed two distinct patterns: 'mesic' environments adjusted concentrations sucrose (through increased levels decreases RWC) response deficit, whereas 'xeric' reductions RWC). root tissues, only xeric contained high mannitol, increasing under WD conditions. suggest that former (mesic) strategy may be beneficial respond short-lasting conditions, because easily metabolized, latter (xeric) relate an effective acclimation longer-lasting drought. These are also related within genus.