Use of a highly sensitive two-dimensional luminescence imaging system to monitor endogenous bioluminescence in plant leaves.
BACKGROUND
All living organisms emit spontaneous low-level bioluminescence, which can be increased in response to stress. Methods for imaging this ultra-weak luminescence have previously been limited by the sensitivity of the detection systems used.


RESULTS
We developed a novel configuration of a cooled charge-coupled device (CCD) for 2-dimensional imaging of light emission from biological material. In this study, we imaged photon emission from plant leaves. The equipment allowed short integration times for image acquisition, providing high resolution spatial and temporal information on bioluminescence. We were able to carry out time course imaging of both delayed chlorophyll fluorescence from whole leaves, and of low level wound-induced luminescence that we showed to be localised to sites of tissue damage. We found that wound-induced luminescence was chlorophyll-dependent and was enhanced at higher temperatures.


CONCLUSIONS
The data gathered on plant bioluminescence illustrate that the equipment described here represents an improvement in 2-dimensional luminescence imaging technology. Using this system, we identify chlorophyll as the origin of wound-induced luminescence from leaves.
Flor-Henry
Michel
M
Biolumonics Ltd., Staveley Mill Yard, Staveley, nr. Kendal, Cumbria, LA8 9LS, UK. michel@biolumonics.com <michel@biolumonics.com>
McCabe
Tulene C
TC
de Bruxelles
Guy L
GL
Roberts
Michael R
MR
D017360:Arabidopsis / Q000737:chemistry / Q000378:metabolism; D002734:Chlorophyll / Q000737:chemistry / Q000378:metabolism*; D005453:Fluorescence; D008163:Luminescent Measurements / Q000295:instrumentation / Q000379:methods*; D018515:Plant Leaves / Q000737:chemistry / Q000378:metabolism*; D015203:Reproducibility of Results; D013050:Spectrometry, Fluorescence / Q000295:instrumentation / Q000379:methods; D013314:Stress, Mechanical; D013696:Temperature; D013997:Time Factors
D002734:Chlorophyll