ISSN 1062-3604, Russian Journal of Developmental Biology, 2008, Vol. 39, No. 2, pp. 78–82. © Pleiades Publishing, Inc., 2008.
Original Russian Text © R.G. Belyaeva, 2008, published in Ontogenez, 2008, Vol. 39, No. 2, pp. 100–105.
Molecular and genetic studies of plant development
rely on genetic collections of both induced and sponta-
neous mutants, which were established for many plant
species, primarily, model species
, etc. These studies demonstrate that
most genes controlling taxonomic morphological char-
acters of the shoot system and ﬂower are regulatory fac-
tors modulating the expression of structural genes
(Doebley and Lukens, 1998; Baum, 1998; Peng et al.,
1999; Theisen et al., 2000; Ezhova and Sklyarova,
2001). However, the identiﬁcation of a gene network
adequately describing inheritance of many ﬂoral muta-
tions does not necessarily describes the modiﬁcation
variation observed in the phenotype of these mutations.
A character can disappear in the phenotype and reap-
pear in the descendants. A considerable fraction of
mutations described for the ﬂoral structure demonstrate
spontaneous phenotypic variation with unstable degree
and kind of expression (penetrance and expressivity) of
the mutant character in individual development. This is
conﬁrmed by the phylogenetic study of our genetic col-
lection of ﬂoral mutation in poppy
L. (Nevkrytaya, 1981; Belyaeva et al., 1983;
Belyaeva, 1995, 1997). Effects of morphogenetic muta-
tions in plants are evaluated at the phenotypic level,
while the mechanism underlying particular phenotypes
can be traced only in ontogeny of this character/organ.
Below we describe phenotypic variation of a new muta-
tion FLORAL MERISTEM UNDETERMINATION in
shoot during individual development
under different conditions of ﬂower formation.
MATERIALS AND METHODS
Experiments were carried out at the Kropotovo Bio-
logical Station (Kol’tsov Institute of Developmental
Biology, Russian Academy of Sciences). The study of
the interaction between the pistillody (
double ﬂowering (
allowed us to identify an F
plant with super-double
ﬂowers and deeply cut leaves.
Several cycles of self-pollination gave rise to a line
with plants carrying a mutant character: the normal
ovary–seed capsule contained a new capsule or individ-
ual ﬂower elements developed in the ovary center.
Long-term self-pollination (more than 10 years) and
selection for the highest character expression allowed
us to produce the line 45 with the shoot FLORAL
MERISTEM UNDETERMINATION mutation. The
mutant character formation was described in individual
development of three consecutively developed ﬂowers
of plants grown in different years with an account of the
penetrance. Plants with no mutant character in three
consecutively developed ﬂowers were considered as
phenotypically normal. The penetrance was the propor-
tion of studied plants in the line with the mutant char-
acter manifested in at least one ﬂower.
is a plant with determi-
nate development forming a monocarpic shoot with a
terminal ﬂower. The line with the shoot FLORAL
MERISTEM UNDETERMINATION mutation was
established after interspeciﬁc and interlinear crosses.
The FLORAL MERISTEM UNDETERMINATION Mutation
: Spontaneous Phenotypic
Variation in Ontogeny
R. G. Belyaeva
Kol’tsov Institute of Developmental Biology, Russian Academy of Sciences, ul. Vavilova 26, Moscow, 119991 Russia
Received December 18, 2006; in ﬁnal form, April 13, 2007
—A new morphogenetic mutation of the shoot, FLORAL MERISTEM UNDETERMINATION, was
L. with monocarpic shoot. The expression of the
(determination of ﬂoral
meristem) gene, which limits the proliferative activity of stem cells in the ﬂoral meristem, was affected. The
mutation displayed spontaneous phenotypic instability in ontogeny, variation in the mutant character expression
on different ﬂowers of the same plant in the same genotypic environment. The mutation phenotype varied from
no expression or formation of individual phyllomes in the center of the primary ovary to formation of a new
ﬂower and a new capsule with viable seeds.
: genetics of plant development, ﬂower morphogenesis, modiﬁcations, variation.