1021-4437/01/4804- $25.00 © 2001
Russian Journal of Plant Physiology, Vol. 48, No. 4, 2001, pp. 518–522. Translated from Fiziologiya Rastenii, Vol. 48, No. 4, 2001, pp. 600–605.
Original Russian Text Copyright © 2001 by Astafurova, Grishin, Zotikova, Klimkin, Matvienko, Romanovskii, Sokovikov, Timofeev, Kharchenko.
The seasonal development of leaves and changes in
environmental factors markedly affect the rate and
rhythms of growth, photosynthesis, and the characteris-
tics of the leaf pigment system in woody plants .
The characterization of the pigment composition in
the photosynthetic apparatus is one of the means used
to assess the physiological condition of plants. At
present, in addition to conventional studies of photo-
synthesis, new informative methods are being sought
for the reliable assessment of the plant condition. The
luminescence methods allowing the noninvasive moni-
toring of changes in plant cells at the membrane and
molecular levels are of ever-growing use . The
remote methods for the diagnostics of the plant condi-
tion, laser probing in particular, are the most interesting
[2, 3]. The most informative are integrated studies that
combine ﬁeld and laboratory experiments.
The goal of this work was to develop a method for
measuring laser-induced ﬂuorescence that can be used
to characterize the pigments of the photosynthetic
apparatus under ﬁeld and laboratory conditions.
MATERIALS AND METHODS
Detached leaves of birch (
were studied under laboratory conditions. The leaves
were collected in the daytime from the middle story of
10- to 30-year-old trees. Time intervals between leaf
detachment and ﬂuorescence spectra recording varied
between 5 and 30 min. The leaves were kept in light
throughout the experiment. Chlorophyll ﬂuorescence
was excited with an ELI-5M Xe–Cl laser at 308 nm
(SKB of Latvian Academy of Sciences). This light
source was used to obtain ﬂuorescence spectra in the
widest possible spectral range. Since luminescence
characteristics are highly sensitive to changes in the
physiological state of plants, the experiments were also
carried out on intact and damaged leaf blades. One half
of a birch leaf was left undamaged, and deep oblique
cuttings were made in the second half of the leaf. Typ-
ically, the ﬂuorescence signal was recorded from a leaf
area of about 1
5 mm in size, with laser-beam scan-
ning along the leaf blade.
The chlorophyll content was measured in acetone
extracts with an SF-26 spectrophotometer (LOMO,
Russia) in three replicate experiments as described in
. Under ﬁeld conditions, measurements were made
in August 1996–June 1997 twice a week, in the eve-
nings and at night. Experiments were performed on
Roth.), aspen (
L.), and 25- to 45-year-old Scotch pine (
L.) trees. The attached leaves were illuminated with a
laser from a distance of 100 m.
For the remote assessment of the variability of the
photosynthetic function and pigment system in plants,
ﬂuorescence was excited by the second harmonic of an
ILTI-405 YAG : Nd laser (Polyus, Russia) at 532 nm.
Remote Probing of Plant Photosynthetic Apparatus
by Measuring Laser-Induced Fluorescence
T. P. Astafurova*, A. I. Grishin**, A. P. Zotikova*, V. M. Klimkin**, G. G. Matvienko**,
O. A. Romanovskii**, V. G. Sokovikov**, V. I. Timofeev**, and O. V. Kharchenko**
*Tomsk State University
**Institute of the Atmospheric Optics, Siberian Division, Russian Academy of Sciences,
Tomsk, pr. Akademicheskii 1, Tomsk, 634055 Russia; fax: 7 (3822) 25-8895; e-mail: email@example.com
Received March 23, 2000
—Laser-induced ﬂuorescence of birch, pine, and aspen trees was studied. The ﬂuorescence of birch
leaves, excited with a Xe–Cl laser at a wavelength of 308 nm, was measured under laboratory conditions.
A persistent directly proportional dependence was found between the measured ﬂuorescence signals and the
chlorophyll content. An apparatus for measuring laser-induced ﬂuorescence under ﬁeld conditions was
designed. Deciduous trees were found to have a wider range of ﬂuorescence variability when compared to coni-
fers, with the ﬂuorescence intensity increasing in the leaves of deciduous trees before the autumn fall of leaves,
during leaf yellowing. It is concluded that the method of lidar probing can be used for identifying tree species
and assessing the condition of leaf and needle canopies.
Key words: Betula pendula - Populas tremula - Pinus silvestris - chlorophyll - laser-induced ﬂuorescence
: ADC—analog-to-digital converter; DCMU—3-
complex; PSI and PSII—photosystems I and II;
—the ratio of
powers of laser signals at 685 and 532 nm.