Functional role of Eucalyptus wood in terms of drought resistance traits: trends at interspecific and intraspecific levels

FERNÁNDEZ M.E.; BAROTTO AJ; MARTINEZ-MEIER A; GYENGE JE; BARIGAH, T.S.; QUIÑONES MARTORELLO, A.; TESÓN N; MERLO E.; DALLA SALDA G; MONTEOLIVA S

Curitiba

Congreso; IUFRO World Congress; 2019

IUFRO

Multispecies surveys have showed that there is a weak but significant tradeoff between xylem efficiency and safety in woody species, and that there are no species occupying the space with high efficiency and high safety. Large vessels and tracheids result in high vulnerability to xylem cavitation (VC) due to tension. Moreover, relationships between xylem structure and function are studied mostly at the interspecific level, with few studies considering the relationships at the intraspecific level, particularly in angiosperms. Recent studies in Quercus species, finding opposite trends in wood anatomy-function relationships considering the interspecies and the intraspecific levels, raises the question about the value of multispecies studies to shed light over what is adaptive within a given species. Eucalyptus species share with Quercus a xylem anatomy composed by solitary vessels surrounded and connected to imperforate tracheary cells and parenchyma, a type of wood anatomy which is poorly understood in functional terms. Contrary to results in that genus, our results in four Eucalyptus species revealed that the trends observed between vessel size (mean and distribution) and VC are similar at the interspecific and intraspecific (E. globulus) levels. No tradeoff was observed between xylem efficiency and safety: the largest the vessels, the lower the VC. The amount of cells around different size-vessels could be involved in this phenomenon. Trends observed in this important forestry genus challenge what we already know about xylem anatomy and function, and may help to widen our vision about the role of wood in adaptation to drought stress.