ISSN 1063-0740, Russian Journal of Marine Biology, 2006, Vol. 32, No. 6, pp. 333–339. © Pleiades Publishing, Inc., 2006.
Original Russian Text © E.A. Titlyanov, T.V. Titlyanova, 2006, published in Biologiya Morya.
is a red alga species widespread
along the coast of Europe and North Atlantic America.
It also grows along the Arctic coast of Russia and on the
Paciﬁc coast of the United States (from Alaska to Cali-
fornia). Probably, the same species occurs on the coasts
of Japan and Korea . According to Perestenko ,
the closely related species
the Far East of Russia. Since ancient times
(Dulse) was traditionally used as a food prod-
uct in England, Scotland, Ireland, and France [8–10].
The dulse was used for preparation of salads, and ﬂakes
and powder were used to season ﬁsh and meat dishes
. Mature thalli of this seaweed, either picked up from
the upper sublittoral or reared in culture, are used in
food . The Dulse is reared as in sea plantations, in
tanks with stirred and aerated culture [2, 11].
Sporophyte and gametophyte (male) plants of
are cultivated at Wadden Sea Station Sylt of
Alfred Wegener Institute for Polar Marine Research in
Bremerhaven at Sylt Island (Germany) in tanks of vol-
ume up to 3 m
ﬁlled with seawater with mineral addi-
tives at intense stirring of thalli by air bulbs. The adult
(commercial) plants, reaching 20 cm length and 5–6 cm
in width, have a purple-red color. All over the thallus,
especially in its upper half, dark convex specks
(Figs. 1A, 1B) of diameter 1.5 mm sometimes similar
to warts (Figs. 1F, 1G, 1H) were observed. It is worth
noting that such specks on thalli of
revealed only in seaweed cultured at Sylt Island; in
other rearing conditions or in nature they either were
absent or have not been noticed [5, 11–13].
“Spottiness” of thalli of red seaweeds is a rather
widespread phenomenon caused by various factors.
First of all, it is considered that numerous small specks
on thalli of red algae might be reproductive organs.
Hence, the red alga
sporiﬁcation period is all covered with the small red-
brown spots of sori of sporangia. In another red alga
, convex cystocarps of 0.9–1.3 mm
diameter also are scattered over the thallus . In the
m) are in the cortical layer of the thallus tight to
each other or are divided by one, two, or by several
rows of cells. Spermatangial sori, scattered over the
greater part of the plant, form colorless or yellowish
cloudlike patches of irregular form .
The other possible type of spots on the thallus sur-
face of red algae is papillar protrusions or proliﬁcations
quite often bearing reproductive organs in them. Thus,
for example, the thallus of the red alga
is always covered by papillae of 0.6–1.3 mm
width and 0.7–1 mm height. The red alga
from the same order Gigartinales has
wartlike papillae. No papilla was revealed on the Pal-
maria thalli [1, 5–7].
In the genus
, the maternal thallus is
branched and proliferates. The proliferation starts from
formation of a dark spot on the thallus (most often near
the rib edge or edge of the thallus) . In old plants of
, both in nature and in culture, young thalli
also germinated from meristem cells of the thallus sur-
face, however, only at the margin of plant .
Meristem Clusters in Cortical Layer of Thallus Cells
of the Cultured Red Alga
E. A. Titlyanov and T. V. Titlyanova
Institute of Marine Biology, Far East Division, Russian Academy of Sciences, Vladivostok, 690041 Russia
Received March 24, 2006
—For the ﬁrst time somatic spotlike formations of 1.5 mm in diameter and height up to 0.5 mm were
revealed in thalli of the red alga
reared in an aerated stirred culture. It was determined that
some cortical cells of the thallus are able to divide in the periclinal and anticlinal directions forming spots. Deep
freezing and subsequent thawing of thalli showed that the cortical cells of spots were meristematic cells. In cer-
tain conditions they enabled the formation of proliﬁcations, which germinated plantlets. These clusters of mer-
istem tissue in the cortical layer of cells of the thallus of
, which were formed in the culture as in
nature, function as growth cells facilitating growth of thalli in thick and natural “planting material” formed upon
thalli fragmenting after their freezing in the winter season.
, meristem formations, cultivation.