ISSN 1062-3604, Russian Journal of Developmental Biology, 2008, Vol. 39, No. 2, pp. 83–91. © Pleiades Publishing, Inc., 2008.
Original Russian Text © A.S. Belorussova, I.N. Tret’yakova, 2008, published in Ontogenez, 2008, Vol. 39, No. 2, pp. 106–115.
In the recent decade, a substantial progress has been
made in the reproduction of woody plants in in vitro
culture. The most interesting results were obtained in
the studies of somatic embryogenesis—a replication
technique providing for extremely high frequency of
plant regeneration in in vitro culture. According to
Batygina (1994, 1999, 2005), somatic embryogenesis
is a new category of vegetative reproduction that leads
to asexual formation of the embryo (embryoid) from a
somatic cell by means of homophasic reproduction
without meiosis and fertilization. As a result, a somatic
cell gives rise to a somatic embryo or embryoid
(embryo-like structure) developing into a plant.
Somatic embryogenesis is a promising model to
study the laws of cell differentiation and realization of
morphogenetic developmental program in embryogen-
esis (Von Arnold et al., 2002).
Somatic embryogenesis was ﬁrst described in in
vitro culture of
(Steward et al., 1958;
Reinert, 1958), and was later induced in a variety of
angiosperms (Batygina, 1999; von Arnold et al., 2002).
In gymnosperms, somatic embryogenesis was induced
much later, ﬁrst, in
(Chalupa, 1985; Hak-
man et al., 1985). To date, gymnosperm regeneration by
somatic embryogenesis was performed in 16 species of
, 11 species of
, 4 species and 2 hybrids of
, 6 species and hybrids of
, and in
(Klimaszewska and Cyr, 2002). The
sources of somatic cells for the somatic embryogenesis
induction in gymnosperms include megagametophytes,
mature and immature embryos and their organs (cotyle-
dons and hypocotyl), needles of young plants (Lelu et al.,
1994a), and segments of vegetative shoots of adult trees
(Malabadi and van Staden, 2005).
Despite active studies of somatic embryogenesis in
gymnosperms in the recent years, plant regeneration
mediated by this technique still remains problematic
for some species. Passing the late stages and generation
of normal embryos capable of germination and produc-
ing normal regenerated plants are the critical points.
Somatic embryogenesis has never been studied in
Siberian larch before. At the same time, Siberian larch
is the major forest-forming species of coniferous for-
ests in East Siberia. Its wood is considered most resis-
tant to decay and is mechanically strong, which pro-
vides for the increasing demand for it. However, this
species has low yield on seed plantations and is suscep-
tible to larch bud gall midge (Baranchikov, 1995). The
development of biotechnologies producing rapidly
growing, highly productive, and larch bud gall midge-
resistant larch trees remains urgent. Common selection
techniques have limited potential in this case. Applica-
tion of efﬁcient innovative technologies involving
somatic embryogenesis in combination with cryo-
preservation and genetic selection should produce,
select, and test for valuable genotypes and then rapidly
distribute them. This should favor massive production
of improved highly productive clones and pure lines of
conifers for clonal forestry (Rao, 1993; Park, 2002).
The goal of this study was to develop efﬁcient bio-
technological methods to replicate different genotypes
of Siberian larch involving somatic embryogenesis and
Patterns of Somatic Embryo Formation in Siberian Larch:
A. S. Belorussova and I. N. Tret’yakova
Sukachev Institute of Forest, Siberian Branch of the Russian Academy of Sciences,
Academgorodok, Krasnoyarsk, 660036 Russia
Received July 10, 2006; in ﬁnal form, July 23, 2007
—Somatic embryogenesis was induced in Siberian larch by in vitro culturing zygotic embryos at dif-
ferent developmental stages. Cultures were grown in modiﬁed Murashige and Skoog medium supplemented
with hormones 2,4-dichlorophenoxyacetic acid (2 mg/l) and 6-benzylaminopurine (0.5–1 mg/l). The success of
somatic embryogenesis in this species depended on the tree genotype and developmental stage of embryos used
for culturing. Somatic embryogenesis from immature zygotic embryos at the stage of cotyledon initiation was
most active. After 5–10 days, such embryos formed the embryogenic tissue including two cell types—elongated
highly vacuolated embryonic tubes and small embryonic cells. Somatic embryos were isolated from proliferat-
ing embryogenic tissues after 2 months of culture.
: cleavage polyembryony, embryogenic tissue, somatic embryos, Siberian larch.