First insights into the functional role of vasicentric tracheids and parenchyma in Eucalyptus species with solitary vessels: Do they contribute to xylem efficiency or safety?

BAROTTO JA; FERNÁNDEZ ME; GYENGE JE; MARTÍNEZ MEIER A; MEYRA A; MONTEOLIVA S

TREE PHYSIOLOGY

OXFORD UNIV PRESS

Lugar: Oxford; Año: 2016

0829-318X

The relationship betweenhydraulic conductivity (ks) and vulnerability to cavitation (VC) with size andnumber of vessels has been studied in many angiosperms. However, few are thestudies linking other cell types (vasicentric tracheids (VT), fibre-tracheids,parenchyma), with these hydraulic functions. Eucalyptus is one of the most important genera in forestryworldwide. It exhibits a complex wood anatomy, with solitary vessels surroundedby VT and parenchyma, which could serve as a good model to investigate the functionalrole of the different cell types in xylem functioning. Wood anatomy (severaltraits of vessels, VT, fibres and parenchyma) in conjunction to maximum ks andvulnerability to cavitation were studied in adult trees of commercial specieswith medium to high wood density (E.globulus, E. viminalis and E. camaldulensis). Traits of cells accompanyingvessels presented correlations with functional variables suggesting that theycontribute to both increasing connectivity between adjacent vessels -and,therefore, to xylem conduction efficiency- and decreasing the probability ofembolism propagation into the tissue, i.e. xylem safety. All three speciespresented moderate to high resistance to cavitation (mean P50values= -2.4 to -4.2 MPa) with no general trade-off between efficiency andsafety at the interspecific level. Results in these species do not support somewell-established hypotheses of the functional meaning of wood anatomy.