Contrasting hydraulic strategies in two tropical lianas and their host trees.
Journal Article (Journal Article)
Premise of the studyTropical liana abundance has been increasing over the past 40 yr, which has been associated with reduced rainfall. The proposed mechanism allowing lianas to thrive in dry conditions is deeper root systems than co-occurring trees, although we know very little about the fundamental hydraulic physiology of lianas.
MethodsTo test the hypothesis that two abundant liana species would physiologically outperform their host tree under reduced water availability, we measured rooting depth, hydraulic properties, plant water status, and leaf gas exchange during the dry season in a seasonally dry tropical forest. We also used a model to compare water use by one of the liana species and the host tree during drought.
Key resultsAll species measured were shallowly rooted. The liana species were more vulnerable to embolism than host trees and experienced water potentials that were predicted to result in substantial hydraulic losses in both leaves and stems. Water potentials measured in host trees were not negative enough to result in significant hydraulic losses. Model results predicted the liana to have greater gas exchange than its host tree during drought and nondrought conditions.
ConclusionsThe host tree species had a more conservative strategy for maintenance of the soil-to-leaf hydraulic pathway than the lianas it supported. The two liana species experienced embolism in stems and leaves, based on vulnerability curves and water potentials. These emboli were presumably repaired before the next morning. However, in the host tree species, reduced stomatal conductance prevented leaf or stem embolism.
- Johnson, DM; Domec, J-C; Woodruff, DR; McCulloh, KA; Meinzer, FC
- February 2013
Volume / Issue
- 100 / 2
Start / End Page
- 374 - 383
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International Standard Serial Number (ISSN)
Digital Object Identifier (DOI)