1. CHLOROPHYLL FLUORESCENCE AS AN INDICATOR OF CROP GROWTH EFFICIENCY
Nicole Williams, Biochemistry
Mentor: Susan Moran,
Maria Pilar Cendrero Mateo
Arizona Space Grant Consortium Symposium
Tucson, Arizona April 20-21, 2012

2. Introduction Photosynthesis efficiency (PE)
Can be used to measure crop health.
Knowing PE can better guide farmers in applying their resources to yield better profits.
X Difficult to directly measure
Photosynthesis is the process in green plants by which carbohydrates are synthesized from carbon dioxide and water using light as an energy source.
Photosynthesis efficiency check, check, ex
Maybe you can finish this slide saying, we propose to measure "Ep" using remote sensing to measure "Plant Chlorophyll fluorescence". And expliain in a simple way what is FLEX and ChF is in the next slide

3. FLuorescence EXplorer
FLEX
FLuorescence EXplorer
Introduce FLEX: It is a satellite that is designed to produce maps of plant fluorescence all over the Earth. Currently, it is being considered by the European Space Agency. If it is funded, it will be launched in 2015.
Fluorescence is considered an easy-to-measure surrogate for photosynthesis efficiency.
This is how it works:
Sunlight reaches the plant. The plant reflects some light, transmits other light, but most of it is used for photosynthesis.
If photosynthesis is efficient, then 1) plants will fluoresce light and 2) leaves will be cool.
If plants are healthy, then fluorescence will be low and leaves will dissipate energy as heat.

4. Hypotheses
1. Fluorescence is negatively correlated with heat dissipation. 2. Fluorescence is an indicator of plant photosynthesis efficiency.
And recall that photosynthesis efficiency is the information that farmers need to make decisions.

5. Experiment Crops Alfalfa (CUF 101) Treatment No stress conditions
Measurements
November 4th and November 6th 2011
Fluorescence baseline measurement at 5 am
Fluorescence measurements from 7 am to 4 pm
Study site
University of Arizona’s Campus Agricultural Center (CAC).
Mike Ottman

6. Measurements LICOR 6400 Measurements: Photosynthesis efficiency
Fluorescence
Heat dissipation
“The main instrument used in this experiment was the LICOR It took measurements of all the desired variable, photosynthesis, photosynthesis efficiency, fluorescence, and heat dissipation, as well as many other measurements. Each measurement was taken individually leaf by leaf. We began at 5am to take dark adapt measurements and then took measurements from 7am to 4pm over two days.”

7. Data Analysis
Time was spent analyzing the data from each leaf using graphs from the data collected by each leaf.
At this point it became clear there were instances of cloud cover or similar circumstances that influenced our measurements.
A great deal of data were collected – it was important to check the data carefully for quality.
Averages
Bad Data

8. Results
We made measurements 8 times during the day from sunrise to sunset. This shows the diurnal trend of fluorescence, photosynthesis efficiency and heat dissipation, related to the light available from the sun (photosynthetically active radiation – PAR).
By making diurnal measurements, we were able to understand how plants respond under varying light conditions.

9. We found a negative relationship between fluorescence and heat dissipation.
pval
0.66
0.026
There is a negative correlation between Fluorescence and heat dissipation.
As healthy leaves conduct photosynthesis, the fluorescence increases and leaves cool due to transpiration. Thus, heat dissipation decreases.
This confirmed our hypothesis #1.

10. Fluorescence and photosynthesis efficiency were strongly correlated.
pval
0.88
0.0017
There is a positive correlation between Fluorescence and Photosynthesis efficiency.
As healthy leaves conduct photosynthesis, the fluorescence increased. This confirmed our hypothesis #2.
Fluorescence is a sufficient surrogate for photosynthesis efficiency.
What does this mean?

11. FLuorescence EXplorer
Concluding Remarks
Fluorescence can provide information to guide farmers in their crop management.
These findings support plans for use of the FLEX satellite to produce global maps of fluorescence.
Future work:
Fluorescence sensitivity to
Crop type
Plant stress
Environmental conditions
FLEX
FLuorescence EXplorer

12. Thank You!