Laser induced chlorphyll fluorescence of plant material
Date
2007-03
Authors
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Publisher
Stellenbosch : University of Stellenbosch
Abstract
Imaging and spectroscopy of laser induced chlorophyll fluorescence (LICF) are emerging as
useful tools in plant physiology and agriculture since these methods allow an early detection
of plant stress and transformation of plant tissue, before visual symptoms appear. Chlorophyll
fluorescence is governed by photosynthetic efficiency and it depends on the plant species
and physiological state. In addition, the laser induced fluorescence of chlorophyll molecules
in the red and far red spectral range is also used to study basic processes and phenomena in
photo-excited molecules. In the work reported here experimental setups used for laser induced
chlorophyll fluorescence imaging and spectroscopy techniques were developed to investigate
chlorophyll fluorescence under constant illumination and also to detect green-fluorescent protein
(GFP) by looking at the chlorophyll fluorescence spectrum and image. He-Ne (wavelength
632 nm), tunable argon ion (wavelength 455 nm), and excimer (wavelength 308 nm) lasers were
used as excitation sources. An Ocean Optics spectrometer was used to record the spectrum
of the chlorophyll fluorescence and the variation of the chlorophyll fluorescence spectrum with
time. The chlorophyll fluorescence spectrum of tobacco leaves expressing GFP was compared
to that of control leaves. A charge-coupled device (CCD) camera was used to image the fluorescence
from GFP expressing and control tobacco leaves to investigate the effect of GFP genes
on chlorophyll fluorescence in relation to the state of the plant material. The spectral analysis
technique and image processing procedures were elaborated in order to obtain better information
on chlorophyll fluorescence. The results of this work show that the experimental setups
and analytical procedures that were devised and used are suitable for laser induced chlorophyll
fluorescence analysis. Fluorescence bleaching could be obtained from the time variation of the
fluorescence spectrum, and plant expressing GFP can be distinguished from control plants by
differences in the laser induced chlorophyll fluorescence.
Description
Thesis (MSc (Physics))--University of Stellenbosch, 2007.
Keywords
Fluorescence, Plant biotechnology, Fluorescence spectroscopy, Fluorescence imaging, Dissertations -- Physics, Theses -- Physics