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Abstract:
The project objective was to determine the degree of plant stress detectable with remote fluorescence measurements in response to application of the stressors: salinity, drought, herbicide, organophosphate-based pesticide, and trampling. All experiments were conducted with Phragmites australis (common reed), a weedy wetland grass common throughout the mid-Atlantic region. The degree of stress was quantified through measured changes in photosynthetic rate, leaf pigment concentrations, stomatal conductance and leaf xylem pressure potential. The trampling pesticide and trampling experiments were inconclusive, there was no evident change in fluorescence. For salinity and herbicide treatment, induced stress was detectable with measurements of fluorescence emission spectra. Stress was evident at 10 ppt salinity and higher, and within 24 hours of herbicide application. Relative to control plants there were significant decreases in fluorescence emission intensity across wavelengths from 678 to 765 nm. Additional preliminary experiments with drought stress revealed significant changes in fluorescence within four days and corresponded to reductions in water relations parameters. For these experiments, fluorescence decreases corresponded to significant decreases in all physiological parameters, except pigment concentrations. For most experiments, decreases in fluorescence were measured before the plants appeared to be visibly stressed. These preliminary results indicate that analysis of fluorescence emission spectra may accurately indicate the onset of stress in plants.
| Limitations: |
 APPROVED FOR PUBLIC RELEASE |
| Description: |
Final rept. 1 Oct 2001-31 Mar 2002 |
| Pages: |
19 |
| Report Date: |
20 DEC 2001 |
| Contract Number: |
DAAD19-01-1-0792 |
| Report Number: |
A897604 |
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Keywords relating to this report:
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