The evolution and function of vessel and pit characters with respect to cavitation resistance across 10 Prunus species.
Various structure-function relationships regarding drought-induced cavitation resistance of secondary xylem have been postulated. These hypotheses were tested on wood of 10 Prunus species showing a range in P50 (i.e., the pressure corresponding to 50% loss of hydraulic conductivity) from -3.54 to -6.27 MPa. Hydraulically relevant wood characters were quantified using light and electron microscopy. A phylogenetic tree was constructed to investigate evolutionary correlations using a phylogenetically independent contrast (PIC) analysis. Vessel-grouping characters were found to be most informative in explaining interspecific variation in P50, with cavitation-resistant species showing more solitary vessels than less resistant species. Co-evolution between vessel-grouping indices and P50 was reported. P50 was weakly correlated with the shape of the intervessel pit aperture, but not with the total intervessel pit membrane area per vessel. A negative correlation was found between P50 and intervessel pit membrane thickness, but this relationship was not supported by the PIC analysis. Cavitation resistance has co-evolved with vessel grouping within Prunus and was mainly influenced by the spatial distribution of the vessel network.
Institute for Systematic Botany and Ecology, Ulm University, Albert-Einstein-Allee 11, D-89081 Ulm, Germany.
Alexander
A
Scholz
David
D
Rabaey
Anke
A
Stein
Hervé
H
Cochard
Erik
E
Smets
Steven
S
Jansen
D000222:Adaptation, Physiological; D005075:Biological Evolution; D001692:Biological Transport; D055864:Droughts; D010802:Phylogeny; D018526:Plant Transpiration / Q000502:physiology*; D027861:Prunus / Q000033:anatomy & histology / Q000235:genetics / Q000502:physiology*; D014867:Water / Q000502:physiology; D014934:Wood / Q000033:anatomy & histology / Q000235:genetics / Q000502:physiology; D052584:Xylem / Q000033:anatomy & histology / Q000235:genetics / Q000502:physiology
D014867:Water
Prunus; bordered pit structure; cavitation resistance; pit membrane; vessel grouping; wood anatomy