1021-4437/02/4904- $27.00 © 2002
Russian Journal of Plant Physiology, Vol. 49, No. 4, 2002, pp. 460–464. Translated from Fiziologiya Rastenii, Vol. 49, No. 4, 2002, pp. 516–520.
Original Russian Text Copyright © 2002 by Bavrina, Lozhnikova, ulaﬁ , Zhivanovich.C
This study initiated by Academician M.Kh. Chaila-
khyan focuses on the effects of light period length (pho-
toperiodism) and light quality on ﬂowering. The effects
of phytohormones, known to control different stages of
plant development and modulate many of the photo-
morphogenetic responses of plants, are also considered.
The dependence of ﬂowering on the photoperiod is
an inherent adaptation to natural day length . The
light quality is very important in this respect [2, 3].
The perception and transduction of the light signal
involved in the photoperiodic ﬂowering response is per-
formed by a series of photosensitive systems, similarly
to other morphogenetic processes. These systems
include different forms of phytochromes [4, 5] and
cryptochromes . Possible involvement of photosyn-
thetic pigments in the photoperiodic control of ﬂower-
ing is considered too [6–8]. Despite numerous works in
this area, it is yet not known how the photoreceptors
regulate ﬂowering in response to variable photoperiods
and light quality .
It is established that the photoperiodic treatment and
light quality substantially affect plant metabolism
including the metabolic conversions and the content of
endogenous phytohormones [10, 11]. The hormones
were proved to exert morphogenetic effects on plants.
For example, gibberellins induce ﬂowering in long-day
species grown under noninductive conditions [1, 12].
Other hormones (cytokinins, auxins, ABA, and ethyl-
ene), taken at certain concentrations, accelerate ﬂower-
ing under photoperiodic conditions [12–14].
All these experiments were conducted on green
plant forms, which complicates the identiﬁcation of the
photoreceptor function [9, 13]. The treatment of plants
with norﬂurazon SANDOZ-9789, a herbicide, provides
the means of obtaining plants devoid of carotenoids and
chlorophyll, without interference with the phytochrome
system [15, 16]. Thus, the effect of photosynthesis and
its products on ﬂowering can be excluded. Chailakhyan
 demonstrated the applicability of such plant
forms for elucidating the mechanisms of ﬂowering con-
trol. Presently, these investigations are being continued.
This study aimed at comparative analysis of ﬂower-
ing in green plants and plants devoid of photosynthetic
pigments grown under various light regimes, as well as
in the absence and presence of exogenous hormones.
MATERIALS AND METHODS
Experiments were performed on
L. plants (a short-day species,
selection form no. 374). Seeds were surface-sterilized
with mercuric chloride (0.1%), placed on a wet ﬁlter
paper in petri dishes, and germinated for 3 days at
Flowering of Cultivated Green and SAN 9789-Treated
Plants Exposed to White, Blue,
and Red Light
T. V. Bavrina*, V. N. Lozhnikova*, L. ulafi **, and B. Zhivanovich**
* Timiryazev Institute of Plant Physiology, Russian Academy of Sciences, Botanicheskaya ul. 35, Moscow, 127276 Russia;
fax: 7 (095) 977-8018; e-mail: email@example.com
** Institute for Biological Research “Sini a Stankovi ”, Yugoslavian Academy of Sciences, Belgrade, Yugoslavia
Received November 26, 2001
—Green plants and plants devoid of photosynthetic pigments were compared with regard to their abil-
ity to ﬂower under various growth conditions. Green plants of
L. and plants treated with
norﬂurazon SANDOZ-9789 (SAN) were grown on sucrose-containing media with or without hormones (GA
BA, IAA, ABA) under short-day photoperiodic or continuous illumination with white, blue, or red light. Green
and SAN-treated albino plants produced ﬂowers only under short-day conditions. The ﬂowering of green plants
was independent of the presence of sucrose and hormones in the medium as well as of the light quality. The
albino plants produced ﬂowers under white and blue light but did not ﬂower in red light. The addition of GA
or BA to the medium induced ﬂowering of albino plants exposed to red light. The functional interaction of pho-
toreceptors in the ﬂowering control is discussed.
Key words: Chenopodium rubrum - day length - light quality - photoreceptors - hormones - SANDOZ-9789 -
: BA—benzyladenine; SD—short day; SANDOZ-
9789 (SAN)—norﬂurazon (4-methylamino-1-(3-triﬂuorome-