Changes of hyperspectral reflectance and photosynthesis in Ambrosia dumosa following supplemental nitrogen additions.
71 CHANGES OF HYPERSPECTRAL REFLECTANCE AND PHOTOSYNTHESIS IN AMBROSIA DUMOSA FOLLOWING SUPPLEMENTAL NITROGEN ADDITIONS
Anthropogenic nitrogen deposition has been increasing in the Mojave desert region due to downwind transport of urban and coastal nitrogen emissions. We examined the possibility of using soil nutrient concentration, photosynthetic gas-exchange and hyperspectral reflectance responses of ambrosia dumosa leaves as a proxy to determine if air pollution is resulting in unnatural fertilization of the Mojave region. Expected nitrogen deposition levels were administered to plants in both field and greenhouse studies. Using ground-based spectroscopy techniques and photosynthetic response curves, a number of metrics for plant physiological function were evaluated. From hyperspectral spectroscopy we determined that nutrient addition has resulted in physiological impacts, but not in the direction expected (i.e. control group showed overall "healthier" values that for fertilized plants). However, there was no significant difference of photosynthesis between control and fertilized groups, thus the changes in reflectance properties may be unrelated to photosynthesis. Further studies are needed to determine the functional significance of reflectance changes, but they nonetheless hold promise for use as proxies to identify alterations in natural soil nutrient concentrations within this human-impacted ecosystem.
A. Cohodas, T. Reilly and D.R. Sandquist. California State University Fullerton, Department of Biological Science, Fullerton, CA, 92834
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|Title Annotation:||POSTER SESSION ABSTRACTS IN PROGRAM ORDER|
|Author:||Cohodas, A.; Reilly, T.; Sandquist, D.R.|
|Publication:||Bulletin (Southern California Academy of Sciences)|
|Date:||Aug 1, 2014|
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