Biologia, Bratislava, 61/1: 11--13, 2006 11
Epiphytic cyanophytes Xenococcus kerneri
and Chamaesiphon minutus on the freshwater red alga
Paralemanea catenata (Rhodophyta)
Pavel Kučera1
, Bohuslav Uher2
& Ondřej Komárek3
1
Department of Botany, Masaryk University Brno, Kotlářská 2, CZ­61137 Brno, Czech Republic;
e-mail: kucerap@sci.muni.cz;
2
Department of Botany, Comenius University Bratislava, Révová 39, SK­81102 Bratislava, Slovakia;
e-mail: uherius@europe.com;
3
Department of Zoology and Ecology, Masaryk University Brno, Kotlářská 2, CZ­61137 Brno, Czech Republic;
e-mail: okomar@sci.muni.cz
Abstract: Epiphytes of Paralemanea catenata (KÜTZING) VIS & SHEATH (Rhodophyta) were studied on material from
the River Dyje in National Park Podyjí. Longitudinal sections of the thalli were made with help of Cryo Cut Microtome
techniques. The epiphytic cyanophytes Xenococcus kerneri HANSGIRG and Chamaesiphon minutus (ROSTAFINSKI)
LEMMERMANN were recognized on the cortex of the thalli. Our observations of the determined species are discussed.
Key words: epiphytic Cyanophytes, Xenococcus, Chamaesiphon, Paralemanea, Czech Republic
Introduction
The freshwater red algae are covered with a great
amount of epiphytic organisms on the surfaces of their
thalli. The epiphytism is determined by occurrence of
the host as well as by the succession conditions for
epiphytes during the season (Kučera & Komárek,
2004).
Freshwater red algae can be common epiphytes
of larger algae, including other Rhodophytes, e. g.
Balbiana investiens (Rieth, 1979; Starmach, 1977),
Audouinella violacea (Kützing) Hamel (Sheath &
Hymes, 1980), and Chroodactylon ramosum (Thwaites)
Hansgirg (Sheath, 1987). Fischer (1956) described
Audouinella hermanni (Roth) Desvaux as
epiphyte on Lemanea fluviatilis (L.) Agardh in Germany,
Sheath & Hymes (1980) recorded 63 epiphytes
on 10 species of red algae in southern Ontario. Kučera
& Komárek (2004) mentioned the epiphytic growth of
Audouinella pygmaea (Kützing) Weber-Van Bosse
on Paralemanea annulata (Kützing) Vis & Sheath
thallus.
Our observations focus on description of the epiphytic
cyanophytes growing on cortex of the red algal
species Paralemanea catenata.
Material and methods
The samples of Paralemanea were collected during the seasons
2000­2004 from the locality Devět Mlýnů (the Dyje
river) in the Czech Republic (latitude 48
49 1 , longitude
15
58 55 , altitude 248 m). All samples were collected from
running water microhabitats with turbulent flow. The plants
grew interspersed in riffles or on weir in partly shaded or well
illuminated parts (KUČERA & KOMÁREK, 2004; KUČERA
& MARVAN, 2004).
In the laboratory, longitudinal sections (20 m in diameter)
were made from thalli of P. catenata with help of Cryo
Cut Microtome. First, the samples were fixed and preserved
in 4% formaldehyde and washed with Sörensen phosphate
buffer. The thalli were placed on frozen discs with 7.5% saccharose
solution. The prepared sections were placed on slides
with chrome gelatine for better adsorption and kept on a
heating plate for one day. The dried specimens were overlaid
by distilled water and embedded in glycerol-gelatine. Photographic
documentation was provided by BX 50 Olympus
microscope equipped with Lucia Image Analysis. The photographs
were made with Nomarski differential interference
contrast microscopy.
Results and discussion
We observed two species of epiphytic cyanophytes on
the thalli of P. catenata: Xenococcus kerneri Hansgirg
1887 (Fig. 1) and Chamaesiphon minutus (Rostafinski)
Lemmermann 1910 (Fig. 2).
Xenococcus kerneri has cells attached to the substrate,
solitary or in monolayered groups, sometimes
forming blastoparenchymatous colonies or a crustose or
flat thin layers with densely arranged cells. The cells
are more or less polarized, sometimes slightly or dis-
12 P. Kučera et al.
Fig. 1. Xenococcus kerneri ­ violet dispersed
cell colonies () on the cortex of Paralemanea.
Scale bar 10 m.
Fig. 2. Chamaesiphon minutus ­ grey-green
cells creating parenchymatous colonies ()
on the cortex of Paralemanea. Scale bar 10
m.
tinctly elongate along the vertical axis. Around the cells
there are usually firm sheaths. In old colonies, the cells
are sometimes organised into short, horizontal, irregular
rows. All cells are more or less of the same size,
at the margin of cell colony usually rounded or elongate,
the cells 4­6 m in diameter (Starmach, 1966;
Komárek & Anagnostidis, 1998). This species was
described by Geitler (1925) and Starmach (1966) as
epiphyte on mosses and green algae in streams, rivers
and lakes. Montejano et al. (1993), Gold-Morgan
et al. (1994) and Montejano et al. (2003) described
three freshwater epiphytic species of genus Xenococcus
from Central Mexico. Komárek & Anagnostidis
(1998) described this species on Lemanea thallus. We
observed this species on the whole surface of Paralemanea
as violet cells in layers, dispersed cell colonies
on the cortex (Fig. 1) or violet dense colonies creating
fan-shaped cell rows arranged on the surface.
Chamaesiphon minutus has solitary cells or cells
in groups, separately attached to the substrate (epiphytic),
ovoid, oval, slightly pear-shaped to shortly
cylindrical with rounded ends, pale blue-green or olive
green, usually with solitary granules, 3.5­6 (8) × 1.5­
3.5 m. Pseudovagina is thin, colourless, usually indistinct,
rarely visible without staining. Exocytes separates
solitarily from the apical cell end (Komárek &
Anagnostidis, 1998). This species was described as
epiphyte on green algae (Cladophora), mosses and filamentous
cyanoprokaryotes (Tolypothrix) in Central Europe,
Argentine and central Mexico (Gold-Morgan et
Epiphytic cyanophytes Xenococcus kerneri and Chamaesiphon minutus 13
al., 1996; Komárek & Anagnostidis, 1998). We observed
this species as grey-green dense parenchymatous
colonies on the cortex (Fig. 2), in some cases covered
by Xenococcus-layers. Ch. minimus Schmidle was described
as epiphyte on red alga Audouinella (Komárek
& Anagnostidis, 1998).
Acknowledgements
We would like to thank to Jaroslava DUBOVÁ for help with
cryo-cut microtome preparation. This work was financially
supported by the grant FRVŠ G4551 to Pavel KUČERA and
by research project MSM 0021622416.
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Received Nov. 25, 2004
Accepted Nov. 10, 2005