Cavitation resistance and seasonal hydraulics differ among three arid Californian plant communities

• Published in: Plant, cell and environment cell and environment, 2007-12, Vol.30 (12), p.1599-1609
• Main Authors: JACOBSEN, ANNA L, PRATT, R. BRANDON, DAVIS, STEPHEN D, EWERS, FRANK W
• Format: Article
• Language: English
• Subjects: Acclimatization - physiology; Agronomy. Soil science and plant productions; arid zones; Biological and medical sciences; California; cavitation fatigue; chaparral; coastal sage scrub; Desert Climate; dry season; Economic plant physiology; Ecosystem; embolism; fluid mechanics; Fundamental and applied biological sciences. Psychology; hydraulic conductivity; leaf habit; leaves; Mojave Desert scrub; native embolism; plant communities; Plant Physiological Phenomena; seasonal variation; Seasons; shrublands; translocation (plant physiology); Water - physiology; water potential; Water relations, transpiration, stomata; water stress; water uptake; wet season; woody plants; xylem; Xylem - physiology
• ISSN: 0140-7791; 1365-3040
• DOI: 10.1111/j.1365-3040.2007.01729.x

Vulnerability to water stress-induced cavitation was measured on 27 woody shrub species from three arid plant communities including chaparral, coastal sage and Mojave Desert scrub. Dry season native embolism and pre-dawn water potential, and both wet and dry season xylem specific hydraulic conductivity (Ks) were measured. Cavitation resistance, estimated as water potential at 50% loss in conductivity (Ψ₅₀), was measured on all species during the wet season and on a subset of species during the dry season. Cavitation resistance varied with sampling season, with 8 of 13 sampled species displaying significant seasonal shifts. Native embolism and water potential were useful in identification of species displaying seasonal shifts. The Ks was not different among sites or seasons. The Ψ₅₀ varied among species and communities. Within communities, interspecific variation may be partially explained by differences in rooting depth or leaf habit (evergreen, semi-deciduous, deciduous). Communities diverged in their Ψ₅₀ with chaparral species displaying the greatest cavitation resistance regardless of sampling season. The greater cavitation resistance of chaparral species is surprising, considering the greater aridity of the Mojave Desert site. Adaptation to arid environments is due to many plant traits, and aridity does not necessarily lead to convergence in cavitation resistance.