Does sample length influence the shape of xylem embolism vulnerability curves? A test with the Cavitron spinning technique.
Plant Cell Environ
; 33(9): 1543-52, 2010 Sep.
Article
en En
| MEDLINE
| ID: mdl-20444214
The Cavitron spinning technique is used to construct xylem embolism vulnerability curves (VCs), but its reliability has been questioned for species with long vessels. This technique generates two types of VC: sigmoid 's'-shaped and exponential, levelling-off 'r'-shaped curves. We tested the hypothesis that 'r'-shaped VCs were anomalous and caused by the presence of vessels cut open during sample preparation. A Cavitron apparatus was used to construct VCs from samples of different lengths in species with contrasting vessel lengths. The results were compared with VCs obtained using other independent techniques. When vessel length exceeded sample length, VCs were 'r'-shaped and anomalous. Filling vessels cut open at both ends with air before measurement produced more typical 's'-shaped VCs. We also found that exposing segments of 11 woody species in a Cavitron at the pressure measured in planta before sampling considerably increased the degree of embolism above the native state level for species with long vessels. We concluded that open vessels were abnormally more vulnerable to cavitation than intact vessels. We recommend restricting this technique to species with short conduits. The relevance of our conclusions for other spinning techniques is discussed.
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Árboles
/
Madera
/
Centrifugación
/
Xilema
Idioma:
En
Revista:
Plant Cell Environ
Asunto de la revista:
BOTANICA
Año:
2010
Tipo del documento:
Article
País de afiliación:
Francia
Pais de publicación:
Estados Unidos