1021-4437/03/5003- $25.00 © 2003
Russian Journal of Plant Physiology, Vol. 50, No. 3, 2003, pp. 324–329. Translated from Fiziologiya Rastenii, Vol. 50, No. 3, 2003, pp. 366–372.
Original Russian Text Copyright © 2003 by Abramova, Avalkina, Golubeva, Pyzhenkova, Golubovskaya.
Callose is a mixture of
-1,3-glucans and is present,
in small quantities, in diverse plant tissues. Among the
physical and physiological properties of callose, note-
worthy is its capacity for rapid synthesis and degrada-
tion. Callose is deposited into the walls of the genera-
tive cell of pollen grains, in somatic cells in response to
wounding, in the phloem, in pericycle ﬁbres, pollen
tubes, root hairs, fungal hyphae, and several other tis-
In all these cases, callose is synthesized in the func-
tioning cells. Its functions depend on its localization
and speciﬁc role in the particular tissues.
Formation of callose walls in meiocytes is a charac-
teristic feature of normally developing anthers and
ovules. Numerous studies of micro- and megasporo-
genesis in angiosperms showed that callose synthesis
begins at the early prophase I of meiosis [1–5].
In grass anthers, callose deposition is conditioned
by the characteristic form and position of microsporo-
cytes and the initial polar outward distribution of cal-
lose in the sporogenous complex. As a result, callose is
mostly deposited in the meiocyte wall facing the inner
loculus of the anther and, to some extent, in the tangen-
tial walls and the walls adjoining the tapetum. In differ-
entiating microsporocytes, large callose ridges are
formed . Similar pattern of callose wall formation
was reported in maize microsporocytes .
In ovules, ﬁrst traces of callose were observed at the
prophase I stage of meiosis, and callose localization
corresponded to the position of the differentiating
megaspore in the tetrad . By the beginning of the
meiotic metaphase I, callose wall completely envel-
oped the megasporocyte.
Our cytoembryological study showed different pat-
terns of callose deposition in several meiotic mutants of
. These observations were primarily
focused on the processes of microsporogenesis. In the
present study, we compared the patterns of callose dep-
osition in micro- and megasporocytes in three maize
), which were in
different way impaired in the meiotic cycle, in order to
relate the process of callose synthesis to these impair-
MATERIALS AND METHODS
Anthers and ovules were sampled from the wild-
type plants of maize (
L.) and the
multiple archesporial cells1
Plants were grown under similar conditions on the
ﬁeld plots of the Pushkin laboratories of the Vavilov
Institute of Plant Industry. Plant material was sampled
starting from the early phase of reproductive organ for-
mation until the prophase I meiocytes developed in the
anthers and until the embryo sac developed in the ears.
To assess whether the plants developed normal or
mutant (underdeveloped) anthers, parts of tassels were
left intact to the anthesis. On the basis of these observa-
tions, we selected normal and mutant samples among
the previously ﬁxed material.
Immature tassels were kept for 24 h in a ﬁxing solu-
tion (40% formaldehyde : glacial acetic acid: 50% eth-
anol, 5 : 5 : 90) and stored in 70% ethanol. The experi-
ments were run for three successive ﬁeld seasons, with
a total score of seven wild-type and 26 mutant plants.
To prepare semithin sections, anthers and ovaries
were embedded in Araldite epoxyresin (Fluka, Switzer-
land) following dehydration procedure used for elec-
tron microscopy. Sections were cut with an ultramicro-
tome, and callose was stained dark blue with the aque-
ous toluidine blue (Sigma, United States) solution.
Cross sections of anthers and longitudinal sections
of ovules were examined.
Synthesis and Deposition of Callose in Anthers and Ovules
of Meiotic Mutants of Maize (
L. I. Abramova, N. A. Avalkina, E. A. Golubeva, Z. S. Pyzhenkova, and I. N. Golubovskaya
Vavilov Institute of Plant Industry, Russian Academy of Agricultural Sciences,
Bol’shaya Morskaya ul. 42, St. Petersburg, 190000 Russia;
fax: 7 (812) 311-8762; e-mail: golub@NA8418.spb.edu
Received September 18, 2001
—The pattern of callose deposition was studied in anthers and ovules of three meiotic mutants of
L. The synthesis of the callose wall in sporogenous cells was related to their transfer to meiotic division.
Key words: Zea mays - mutants - meiocytes - anther - ovule - callose synthesis