ISSN 1021-4437, Russian Journal of Plant Physiology, 2006, Vol. 53, No. 6, pp. 762–767. © MAIK “Nauka /Interperiodica” (Russia), 2006.
Original Russian Text © A.S. Minich, I.B. Minich, N.S. Zelen’chukova, R.A. Karnachuk, I.F. Golovatskaya, M.V. Eﬁmova, V.S. Raida, 2006, published in Fiziologiya Rastenii,
2006, Vol. 53, No. 6, pp. 863–868.
Light regulates plant growth and morphogenesis.
Distinct from the photosynthetic machinery, the struc-
tural and molecular apparatus is responsible for initial
stages of biological responses to low-energy light,
which is extremely sensitive to changes in light quality
[1–3]. Changes in the light ﬂow result in the changes in
plant morphogenesis, which are primarily connected
with modulation in light intensity in different spectrum
regions [2, 3].
It was supposed that endogenous phytohormones
are involved into the control of photomorphogenesis,
and their balance depends on light quality [4–6]. How-
ever, the relation between the light ﬂow and the level of
endogenous hormones is poorly studied [6, 7]. The
characterized by a low sensitivity and a weakened mor-
phogenetic response to deﬁnite PAR regions is very
beneﬁcial approach to study such relations [8–10].
The objective of this study was to elucidate the
effects of low intensity red luminescent radiation with
a maximum of 617 nm on
MATERIALS AND METHODS
We used three lines of
ecotype: wild-type Ler plants
and two photoreceptor mutants,
by Koornneef et al. . The
mutant is defective in
the structure of the
gene and is characterized by
a weakened response to the red part of the spectrum .
mutant is defective in the structure of the
gene and is poorly sensitive to blue and UV-A light dur-
ing seedling photomorphogenesis .
seedlings were grown under white light
supplemented with UV-A (irradiances were 63 and
, respectively) according to the following
scheme: 8 h of darkness/4 h of white light/6 h of white
light + UV/6 h of white light. Light sources were lumi-
nescent lamps LB-40 and LD-40 and the PL-S 9W/08
Black Light UV-lamp (Philips, The Netherlands).
Polyethylene ﬁlm displaying different photophysical
m in thickness served as a light ﬁlter; it
was positioned at a distance of 20 cm from the light
source. Unmodiﬁed ﬁlm served a control; light-correct-
ing ﬁlm had similar characteristics but contained a pho-
toluminophor (0.1%, w/w;
produced in the reaction of europium nitrate with 1.10-
phenanthroline) . Photophysical ﬁlm characteris-
The Role of Low Intensity Red Luminescent Radiation
in the Control of
and Hormonal Balance
A. S. Minich
, I. B. Minich
, N. S. Zelen’chukova
, R. A. Karnachuk
, I. F. Golovatskaya
M. V. Efimova
, and V. S. Raida
Faculty of Biology and Chemistry, Tomsk State Pedagogical University, Komsomol’skii pr. 75, Tomsk, 634041 Russia;
Departments of Plant Physiology and Biotechnology, Tomsk State University, Tomsk
Institute of Petrochemistry, Siberian Division, Russian Academy of Sciences, Tomsk
Received December 13, 2005
—The effects of low intensity red luminescent radiation emitted by the polyethylene light-correcting
ﬁlm due to the conversion of UV-A radiation on
(L.) Heynh. morphogenesis and hormonal
balance were studied. Wild-type Ler plants and two mutants,
, displaying disturbances in the syn-
thesis of phytochrome B and cryptochrome 1, respectively, were compared. In wild-type and
under the light-correcting ﬁlm, growth and development were substantially accelerated, whereas, in
they were retarded. These changes were correlated with changes in the levels of endogenous hormones, both
growth activators and inhibitors. We concluded that low intensity red luminescent radiation affected the plant
hormonal balance. In its turn, the changes in the hormone ratios, growth stimulators and inhibitors, affected the
rate of plant growth and their productivity.
Key words: Arabidopsis thaliana - wild-type Ler plants - hy4 and hy3 mutants - low intensity red luminescent
radiation - growth - endogenous hormones - morphogenesis
: CRY1—cryptochrome 1; PAR—photosyntheti-
cally active radiation; PHYB—phytochrome B.