| Autor: |
John D. Krenz, Michael J. Dyslin, Christopher T. Ruhland |
| Rok vydání: |
2013 |
| Předmět: |
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| Zdroj: |
Journal of Arid Environments. 96:19-22 |
| ISSN: |
0140-1963 |
| DOI: |
10.1016/j.jaridenv.2013.04.005 |
| Popis: |
The flux of biologically-effective ultraviolet radiation (UV) is diminished by atmospheric absorption which may cause physiological and morphological phenotypic differences among plant populations at different elevations. We examined UV-screening effectiveness of leaves of Artemisia tridentata ssp wyomingensis (Wyoming big sagebrush) along an 800-m elevation gradient in North-central Wyoming with a pulse-amplitude modulated fluorometer. Adaxial epidermal transmittance of UV increased at lower elevations; means ranged from 2.3% (high elevation) to 10.2% (low elevation). To provide a proximate explanation for this relationship, we collected leaves across the gradient and estimated concentrations of bulk-soluble UV-absorbing compounds (λ = 300 and 365 nm) and the density of trichomes on the adaxial surface. Concentrations of UV-absorbing compounds decreased with elevation and ranged from 0.64–2.25 A300 cm−2 and 0.43–1.35 A365 cm−2. Trichome density increased from 14,400 cm−2 at low elevation to 22,500 cm−2 at high elevation. Because the distance along the elevation gradient was only 18 km, gene flow likely prevents ecotypic differentiation; the ultimate cause of the ecocline in screening effectiveness is likely the evolution of environmentally-induced phenotypic plasticity in both biochemical and anatomical properties of leaves in response to variation in UV irradiance. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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Full Text from ScienceDirect