ISSN 1021-4437, Russian Journal of Plant Physiology, 2006, Vol. 53, No. 3, pp. 289–297. © MAIK “Nauka /Interperiodica” (Russia), 2006.
Published in Russian in Fiziologiya Rastenii, 2006, Vol. 53, No. 3, pp. 325–335.
Delayed ﬂuorescence (DF) phenomenon can be
described as lighting of green plants, algae, and photo-
synthetic bacteria in red range of the visible spectrum,
immediately upon their illumination. In the ﬁnal step,
DF is created by the same S
prompt ﬂuorescence [1, 2]. But very different lifetimes,
1.5 ns or less for prompt ﬂuorescence [3, 4] compared
to nanoseconds [5, 6], over microseconds [7, 8], and
milliseconds [9, 10] to second range  for DF,
clearly indicate two very distinct mechanisms by which
state of chlorophyll (Chl) is created. In
the case of prompt ﬂuorescence, the S
state is achieved
s period by internal conversion,
following light absorption. In the case of DF, the S
state is created through a recombination of products
formed in the primary photochemical act [12, 14].
Therefore, unlike prompt ﬂuorescence, which does not
need more than a single Chl molecule to be emitted, the
entire entity of the photosynthetic apparatus is neces-
sary for DF emission, i.e., DF has been used as a cri-
terion for its integrity .
Delayed ﬂuorescence induction trace reﬂects pro-
cesses and phenomena occurring when a photosynthe-
sizing object is being kept in darkness for a while, and
then illuminated, i.e., at a transition period from dark to
light regime. Most DF induction traces were recorded
under the millisecond operating conditions of a rotating
disc, with intermittent illumination, consisting of a few
milliseconds of light period, and consecutive few milli-
seconds of darkness in which DF was being recorded
[16, 17]. The overall shape of a DF induction trace is
highly dependent on the length of the dark period pre-
ceding illumination [18, 19]. If the preceding dark
) is longer than 30 and shorter than 300 s, DF
induction trace is split into at least three transients .
Clearly, distinct appearance time of their maxima
suggests that their origins are due to various processes
Transients of Delayed Fluorescence Induction Signal
and Photosynthetic Antennas: A Possible Relationship.
Mathematical Modeling Approach
, D. Z. Markovi
, and . N. Radenovi
Center for Multidisciplinary Studies, University of Belgrade, Despot Stefan Blvd. 142,
11000 Belgrade, Serbia and Montenegro;
fax: +381(11)76-1433; e-mail: email@example.com
Faculty of Technology, University of Ni , Leskovac, Serbia and Montenegro
Maize Research Institute, Belgrade–Zemun, Serbia and Montenegro
Received May 27, 2005
—A mathematical model was developed for resolved temporal transients of experimentally recorded
delayed ﬂuorescence (DF) induction signal. During an intermittent light regime, antennas of the photosynthetic
apparatus were treated as targets, repeatedly hit by potentially absorbable photons within a series of consecutive
light ﬂashes. Formulas were derived for the number of antennas, cumulatively hit by a speciﬁc number of pho-
tons, as a function of the ﬂash serial number (time). Model parameters included number of absorbable photons
in one ﬂash, antenna sizes, and their number. A series of induction curves were analyzed, obtained from a
leaf segment and differing in the previous dark period (
). Each curve, consisting of the two most prom-
inent DF transients (
), was ﬁtted with several model types, differing in the number of absorbed photons.
For both transients, the best ﬁtting result was achieved when DF induction was linked to the second absorbed
photon. As expected, model parameters related to antenna sizes showed weaker dependence on
referring to antenna number. With restrictions applied to this model, the two DF induction transients may be
related to two classes of photosynthetic antennas. Their different sizes may have a predominant inﬂuence on
the efﬁciency of photon absorption and possibly time-dependent appearance of DF transients.
Key words: Zea mays - delayed ﬂuorescence - induction transients - mathematical modeling - photosynthetic
: Chl—chlorophyll; DF—delayed ﬂuorescence;
The text was submitted by the authors in English.