ISSN 1021-4437, Russian Journal of Plant Physiology, 2006, Vol. 53, No. 4, pp. 530–534. © MAIK “Nauka /Interperiodica” (Russia), 2006.
Published in Russian in Fiziologiya Rastenii, 2006, Vol. 53, No. 4, pp. 592–596.
Genetic transformation technique has been emerg-
ing as a tool supplementary to conventional breeding
. It provides the possibilities to directly manipulate
the heritable genetic material, resulting in new combi-
nations of traits or functions, which could not be previ-
ously achieved by conventional breeding methods [1, 2].
An efﬁcient tissue culturing is a prerequisite for plant
improvement through genetic transformation .
The induction of friable embryogenic callus is very
sensitive to culture conditions, i.e., composition of
medium, physical environment of the culture, geno-
type, and explant source.
The involvement of ethylene in plant tissue growth
and differentiation has been widely investigated .
Ethylene is produced by cultured plant cells  and
possibly by the gelling agent like agar in culture
medium . Application of ethylene precursors and
inhibitors has shown that ethylene might often have the
diverse effects in similar tissue culture systems.
Although it has been reported that ethylene could pro-
mote callus growth , it generally appears to inhibit
somatic embryogenesis and shoot regeneration [4, 8,
9]. Ethylene stimulated microspore division, whereas it
inhibited callus development in the anther culture of
durum wheat and barley .
Silver nitrate, a potent inhibitor of ethylene action
, was shown to improve somatic embryogenesis in
tetraploid potato (
L.), barley (
L.) [12, 13].
has been used suc-
cessfully in several monocotyledonous species to
enhance friable embryogenic callus production, such as
L.), emmer wheat (
(Schrank) Schübler), and durum wheat (
Desf.) [9, 14, 15]. It also stimulated callus growth in
L.) and plant regeneration in maize
[16, 17]. However, poor information about the effects
on the immature embryo culture of common
L.) is available.
As one of the most important food crops, common
wheat has been extensively investigated with respect to
genetic improvement. However, wheat is characterized
by a large and complicated genome, thus resulting in
difﬁcult establishing an excellent transformation sys-
tem . The wheat tissue culture, embryogenic callus
induction from wheat immature embryos in particular,
is inﬂuenced by many factors, such as embryo size,
genotype, culture medium, and so on [18–21]. In order
to develop a more efﬁcient embryogenesis in wheat
immature embryo culture for genetic transformation,
the objective of this study was to investigate both the
and of the interactions between gen-
otype pattern and
concentrations on the
response of wheat immature embryos in tissue culture.
MATERIALS AND METHODS
Plant materials and media.
Four common wheat
genotypes with desirable agronomic and yield charac-
Effects of Silver Nitrate on the Tissue Culture
of Immature Wheat Embryos
L. M. Wu
, Y. M. Wei
, and Y. L. Zheng
Triticeae Research Institute, Sichuan Agricultural University, Dujiangyan, 611830 China;
fax: (+86) 835 288-3153; e-mail: firstname.lastname@example.org;
Biotechnology College, Jilin Agricultural University, Changchun, 130118 China
Received July 20, 2005
The immature embryos of four common wheat (
L.) genotypes with desirable
agronomic traits were evaluated for their tissue culture response to ethylene antagonist, silver nitrate, added to
callus-inductive and subculture media at six concentrations. The addition of
embryogenic callus frequency and callus growth, but reduced the necroses and almost did not affect callus
induction frequencies. Strong genotypic effects on callus induction, embryogenic callus formation, and necro-
sis frequency were observed. It was also found that there were signiﬁcant interactions between genotype and
concentrations affecting embryogenic callus frequency and callus growth index. In general, 10 mg/l
concentration may be considered most favorable for embryogenesis and prevention of necroses; at the same
time, it did not reduce callus induction and promoted callus growth.
Key words: Triticum aestivum - callus induction - immature embryo - silver nitrat
The text was submitted by the authors in English.