Seasonal changes in carbohydrates, cyclitols, and water relations of 3 field grown Eucalyptus species from contrasting taxonomy on a common site

Alterations in plant chemistry underpin a suite of physiological adaptations to arid conditions. Qualitative and quantitative differences in leaf chemistry are found in the genus Eucalyptus correlating with physiological adaptation to aridity. • Here we investigate seasonal water relations of three field grown eucalypt species grown at a common site known to differ in their ability to accumulate the cyclic sugar alcohol, quercitol. • We show that quercitol contributes significantly to osmotic relations in field grown trees of Eucalyptus melliodora but is present only in trace amounts in E. rubida and E. obliqua. • Measured concentrations of quercitol account for the difference in osmotic potentials between species and can be interpreted as a mechanism for adaptation to low water availability. © INRA, EDP Sciences, 2009.