Xylem cavitation and hydraulic control of stomatal conductance in Laurel (Laurus nobilis L.)

Citation
S. Salleo et al., Xylem cavitation and hydraulic control of stomatal conductance in Laurel (Laurus nobilis L.), PL CELL ENV, 23(1), 2000, pp. 71-79
Citations number
57
Categorie Soggetti
Plant Sciences","Animal & Plant Sciences
Journal title
PLANT CELL AND ENVIRONMENT
ISSN journal
01407791 → ACNP
Volume
23
Issue
1
Year of publication
2000
Pages
71 - 79
Database
ISI
SICI code
0140-7791(200001)23:1<71:XCAHCO>2.0.ZU;2-C
Abstract
The possible link between stomatal conductance (g(L)), leaf water potential (Psi(L)) and xylem cavitation was studied in leaves and shoots of detached branches as well as of whole plants of Laurus nobilis L. (Laurel). Shoot c avitation induced complete stomatal closure in air-dehydrated detached bran ches in less than 10 min. By contrast, a fine regulation of g(L) in whole p lants was the consequence of Psi(L) reaching the cavitation threshold (Psi( CAV)) for shoots. A pulse of xylem cavitation in the shoots was paralleled by a decrease in g(L) of about 50%, while Psi(L) stabilized at values preve nting further xylem cavitation. In these experiments, no root signals were likely to be sent to the leaves from the roots in response to soil dryness because branches were either detached or whole plants were growing in const antly wet soil. The stomatal response to increasing evaporative demand appe ared therefore to be the result of hydraulic signals generated during shoot cavitation. A negative feedback link is proposed between g(L) and Psi(CAV) rather than with Psi(L) itself.