Emmett Chappelle

Development of laser-induced fluorescence methods for determining plant stress and differentiating species

Contributed by: Matt Carey @Catt_Marey



Abiotic stressors, Agriculture, Cancer, Development, Historical figure, Lab, Medicine, North America, Physiological/organismal ecology, Plants, Race/ethnicity, Technology, Terrestrial, Theory/Computational



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Emmett W. Chappelle, Frank M. Wood, James E. McMurtrey, and W. Wayne Newcom. 1984. Laser-induced fluorescence of green plants. 1: A technique for the remote detection of plant stress and species differentiation. Vol. 23, Issue 1, pp. 134-138 (1984) link



Slide 1: Researcher’s Background

Emmett was an American biochemist, exobiologist and astrochemist that did interesting work in the area of luminescence.

Biography in brief

Emmett W. Chappelle was an American scientist who lived from October 24, 1925 – October 14, 2019. He was born in Phoenix, Arizona where his family ran a small farm. Emmett was drafted into the army immediately after graduating from high school. He received his B.S in biology from UC Berkeley with help from the GI Bill. Emmett went on to get his M.S. in biology from the University of Washington and worked as a research associate at Stanford University. He later worked for NASA as a part of the Goddard Space Flight Center. His research involved the use of firefly chemicals that glow in the presence of ATP, which can be used as a biological assay. His broad work surrounding luminescence led to the development of an assay for the detection of ATP in cells, the development of methods for detecting the quantity of bacteria in liquids, determining the health of crop vegetation via laser-induced fluorescence, and methods for potentially detecting extraterrestrial biology used on NASA’s Viking spacecrafts that were sent to Mars in the mid 1970s.

Is (or was) their research under-valued because of their identity?



Slide 2: Research Overview

Take home message of study

The fluorescence spectra of green plants can vary due to species differences and in response to stress. Differences in patterns of laser Induced fluorescent measurements provide a potential technique for the remote detection of plant stress and plant species.

Study system

Plant leaves of various stress levels (i.e. watered or unwatered) from two species (soy, shown in photo, and corn) were exposed to a pulsed nitrogen laser emitting at 337 nanometers and their fluorescence spectra were recorded.



Slide 3: Key Research Points

Main figure

This figure highlights the effect of dehydration on the fluorescence of soybean leaves.The x-axis displays the wavelength of light measured on a range from 400 to 800 nanometers, representing the full range of visible light. The y-axis shows the spectral intensities as relative fluorescence intensity (RFI) units.The lines show the laser-induced fluorescence spectra (LIF) of unwatered (top line) and watered (bottom line) soybean leaves. The distinct patterns of LIF measurements observed between water treatments provide a potential technique for the remote detection of  plant stress.


Societal Relevance

The novel fluorescence methods introduced by Emmett W. Chappelle allow for the remote detection of plant stress and species, the quantification of bacteria in liquids, and the potential identification of extraterrestrial biology.


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