1063-0740/03/2904- $25.00 © 2003
Russian Journal of Marine Biology, Vol. 29, No. 4, 2003, pp. 251–254.
Original Russian Text Copyright © 2003 by Biologiya Morya, Aleksandrova, Levchenko, Reunov.
The speciﬁc features of the formation of reproduc-
tive organs and the ultrastructural organization of
gametes in red algae (Rhodophyta) are used in increas-
ing frequency as a supplementary criterion in the phy-
logeny of this group [7, 16, 18]. In the genus
such comparative investigations have been performed
McLachlan et Oliveira ;
(Montagne) Howe, and
(Bird et Oliveira) Fredericq et Hommersand
. Three morphological types of male reproductive
organs have been distinguished as characteristic of the
algae of the genus
and identiﬁed as “verru-
cosa,” “textori,” and “chorda,” which allows us to make
a conclusion about phylogenetically dependent diver-
sity in the structure of male reproductive organs. How-
ever, the ultrastructural data obtained do not allow us to
reveal any interspecies differences in the differentiation
or structure of male gametes (spermatia). This fact is
relevant for further investigations, as the thesis about
the species speciﬁcity of male gametes is generally
accepted in modern spermatology. This hypothesis,
advanced by Retzius  in the early 20th century for
some multicellular animals was later conﬁrmed for
many taxons of Metazoa. At present, the structural
peculiarities of spermatozoa are considered as one of
the factors prohibiting interspecies cross-breeding and
should any examples of interspecies “uniformity” of
male gametes be found in animals or plants, scientists
would have to explain such a particular phenomenon.
This paper described for the ﬁrst time at the ultra-
structural level the speciﬁc features of the formation
and structure of male gametes in the red alga
MATERIALS AND METHODS
The thalluses of male gametophytes of
in the reproductive stage were collected in
May 2001, from a depth of 0.5 m, in Vostok Bay, Sea of
Japan, in the vicinity of “Vostok” Marine Biological
Station of the Institute of Marine Biology FEB RAS.
The samples for TEM were ﬁxed by a 2.5% glutaralde-
hyde solution in a 0.05 M cacodylate buffer containing
25 mg/ml NaCl, with subsequent postﬁxation with a
2% solution of osmium tetroxide in the same buffer.
After rinsing in the buffer, the samples were dehydrated
in a series of alcohol and acetone and embedded into a
Spurr epoxy resin. Thin sections (55 nm) were made
with a Reichert-Ultracut E, contrasted by uranyl acetate
and lead citrate and examined with a JEOL-JEM 100B
transmission electron microscope.
The male gametes of
in conceptacles, whose structure agrees with the type
“verrucosa” . On the thallus of the alga the areas of
localization of the conceptacles look like pale spots
clearly visible among pigmented cells.
Differentiation of Male Gametes in
Ya. N. Aleksandrova, E. V. Levchenko, and A. A. Reunov
Institute of Marine Biology, Far East Division, Russian Academy of Sciences, Vladivostok, 690041 Russia
Received March 24, 2003
—The development of male gametes (spermacia) in the red alga
has been stud-
ied using methods of transmission electron microscopy. Early spermatangia located along the wall of the con-
ceptacle show an elongated shape in the thin sections. In the central part of the electron-dense cytoplasm of
these cells there is a nucleus; numerous ﬁbrous vesicles are arranged in the periphery. During the process of
differentiation, the spermatangia become more rounded in shape and a large spermatangial vesicle is developed.
The subsequent development of spermatium is accompanied by polarization of the spermatangium and the sub-
sequent excretion of the spermatangial vesicle. The spermatia are oval cells containing a nucleus and ﬁbrous
vesicles. The process of differentiation of male gametes in
does not differ from that in ﬁve species
of the genus
, where it has already been studied. However, any conclusions about the degree of sim-
ilarity between the spermatia in all the studied species can be made only after a detailed comparative analysis
of the ultrastructural characteristics of these gametes.
, spermatangium, ultrastructure, red algae.