INVESTIGADORES
FERNANDEZ Maria Elena
artículos
Título:
Dynamics of cavitation in a Douglas-fir tree-ring: transition-wood, the lord of the ring?
Autor/es:
DALLA SALDA G; FERNÁNDEZ M.E.; SERGENT AS; ROZENBERG P; BADEL E.; MARTÍNEZ MEIER A
Revista:
The Journal of Plant Hydraulics
Editorial:
INRA
Referencias:
Lugar: Clermont Ferrand; Año: 2014 vol. 1 p. 1 - 5
ISSN:
2268-4565
Resumen:
The
objective of this work was to investigate the dynamics of embolism formation
within a Douglas-fir tree-ring. Four resistant and four vulnerable 10-year-old trees
were selected among 50 trees, based on their P50. Stem samples,
taken next to those used to obtain the vulnerability to cavitation curves, were
collected and submitted to increasing positive pressures, in order to simulate
increasing tension caused by water stress in the xylem. Then the conductive surface
of the samples was stained and scanned and the images were analyzed. X-ray
microdensity profiles were obtained on the same samples. The microdensity
profiles of the 2011 ring were analyzed in three parts, earlywood,
transition-wood and latewood. The dynamics of embolism propagation was observed
separately in these three parts. Our results showed that the initiation and the
propagation of the cavitation follow a discrete trend, with at least two
successive initiation events: first cavitation initiates and propagates rapidly
in the latewood. Then, a second cavitation event begins and spreads in the earlywood
and eventually propagates to the transition-wood, which remains the last
conductive part in the ring before full embolism. We observed that resistant to
cavitation trees showed lower transition-wood density than vulnerable to
cavitation trees.