Physiological responses of tagasaste to a progressive drought in its native environment on the Canary Islands

• Published in: Environmental and experimental botany 2005, Vol.53 (2), p.195-204
• Main Authors: González-Rodrı́guez, A.M., Martı́n-Olivera, A., Morales, D., Jiménez, M.S.
• Format: Article
• Language: English
• Subjects: Animal, plant and microbial ecology; Anisohydric plants; Applied ecology; Biological and medical sciences; carbon dioxide; Chamaecytisus prolifer var. palmensis; chlorophyll; CO 2 assimilation rate; diurnal variation; drought; Ecotoxicology, biological effects of pollution; Effects of pollution and side effects of pesticides on plants and fungi; fluorescence; Fundamental and applied biological sciences. Psychology; gas exchange; Mediterranean species; photosystem II; plant response; plant stress; seasonal variation; soil water content; Stomatal conductance; stress tolerance; vapor pressure; water content; water stress; Water use efficiency
• ISSN: 0098-8472; 1873-7307
• DOI: 10.1016/j.envexpbot.2004.03.013

Diurnal courses of gas exchange, chlorophyll fluorescence, shoot water potential ( Ψ) and leaf relative water content (RWC leaf) were recorded in Chamaecytisus proliferus (L. fil.) Link ssp. proliferus var. palmensis (Christ) (tagasaste) growing in natural conditions in the North-West slope of Tenerife, Canary Islands. During the studied period (April–July 2000), the soil relative water content (RWC soil) progressively decreased, while the air vapour pressure deficit increased. As a consequence a decrease in Ψ and RWC leaf took place as well as a decrease in stomatal conductance ( g s) and CO 2 assimilation rate ( A). These characteristics, typical of an anisohydric plant, allowed this species to endure a mild drought. Photochemical efficiency of PSII ( φ PSII) followed the inverse pattern to that observed for the photosynthetic photon flux density (PPFD), decreasing at midday and recovering during the late afternoon. This recovering at the end of each day, and the constant values of the maximum quantum yield of PSII photochemistry ( F v/ F m) during the studied period, indicate that there was no permanent damage to the photosynthetic apparatus due to mild water stress.