Differentiation among populations of Sedum wrightii (Crassulaceae) in response to limited water availability: water relations, CO2 assimilation, growth and survivorship

Sedum wrightii is one of only a few species in the Crassulaceae for which there is evidence for a high degree of variability in the ratio of daytime to nighttime CO₂ assimilation. There are both environmental and genetic components to this variability. S. wrightii grows over a wide altitudinal gradi...

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Bibliographic Details
Published in:Oecologia 1986-09, Vol.70 (2), p.198-204
Main Authors: Gurevitch, J, Teeri, J.A, Wood, A.M
Format: Article
Language:English
Subjects:
altitude
Animal and plant ecology
Animal, plant and microbial ecology
Autoecology
Biological and medical sciences
Canyons
Carbon dioxide
Crassulacean acid metabolism
Drought
Ferns
Fundamental and applied biological sciences. Psychology
genetic variation
Genotypes
Leaves
mortality
photosynthesis
Plants
Plants and fungi
Population growth
Sedum
water availability
water relations
Water use efficiency
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Summary:Sedum wrightii is one of only a few species in the Crassulaceae for which there is evidence for a high degree of variability in the ratio of daytime to nighttime CO₂ assimilation. There are both environmental and genetic components to this variability. S. wrightii grows over a wide altitudinal gradient. The purpose of this study was to compare low, intermediate, and high altitude populations with respect to the degree of CAM expression and the capability to tolerate limited water availability. We utilized clonally-replicated genotypes of plants from each population in common environment greenhouse experiments. Genetic differences among the populations were found in long-term water use efficiency, in 24 hour CO₂ exchange patterns, in biomass δ13C values, in carbon allocation, and in water status and ultimately survival during prolonged drought. The differences among the populations appear to be closely related to differences in the native habitats. The low altitude, desert plants had the greatest ability to grow and survive under conditions of limited water availability and appear to have the greatest shift to nighttime CO₂ uptake during periods without water, while the high altitude plants had the poorest performance under these conditions and appear to shut down net carbon uptake when severely water limited.
ISSN:0029-8549
1432-1939
DOI:10.1007/BF00379240