Budapest 1974 - Magyar Természettudományi Múzeum

ANNALES HISTORICO-NATURALES MUSEI NATIONALES HUNGARICI
Tomus 66. Budapest 1974.
Filamentous Algae in Városligeti-tó, Budapest
By L. HAJDÚ, Budapest
Abstract — From the Városligeti-tó (Budapest) five filamentous algal species were
identified of wich Spirogyra crassoidea TRANSEAU and Oedogonium tyrolicum WITT-
ROCK are new in the Hungarian Flora. With Spirogyra crassoidea it is not possible
to ascribe taxonomic value either to the length of the spore or that of cell for a correlation
of + 0,6594 (p < 1%) between them. A relationship is suggested to exist between
a rapid decrease of water level and the spore formation of Spirogyra. — 8 figures.
Floristical data
In the autumn of 1972 I observed a thick-threaded Spirogyra in the Városligeti-tó
(-ornamental pond of Budapest town park). The specimen was unfortunately on the
vegetative state. In 1973 I examined that part of the pond which was covered with
concrete thoroughly hoping to find also specimens in the proliferative state without
whicht it is impossible to identify the species. In the course of my studies in the lake
I identified the following five filamentous algal species :
1. Spirogyra crassoidea TRANSEAU (= S. ellipsospora var. crassoidea TRAN-
SEAU) — The vegetative cells have widths of 118—148 jum, and lengths of 201—314
pm. The cross-wall is straight and each cell contains 5—8 spiral chloroplasts.
Copulation is ladder shaped, the copulating cells do not swell. The copulation
channel averaging 27 pm in width, is formed jointly by the two partners. The
zygotes are three-axed, elliptic, their centers are often indented and thus suggestive
of human blood cell (Fig. 1). The length of the spore is 112—157,5 pm, the width
129—158 jitm. The external wall of the spore is thin, its surface is smooth. The
mesosporium is brownish and on its surface small points arranged in irregular
pattern are visible under the immersion lens.
In August the cells contained many calcium oxalate crystals which often measured
up to 20 jtim (Fig. 2). The pyrenoids were about 10 pm in diameter. The description
well conforms to the data in the literature.
Nearly every author dealing with the systematics of the Spirogyra genus
agrees in that in the case of intercalarily growing cells the cell-length is of no importance
from taxonomical view-point. LANGER (1934) for instance writes the
following: " I neglected to publish the lengths of the cells. These are, namely, of
no importance, since the length of the cell is the function of the age of the cell and
as such cannot be taken for a diagnostic character of the species". Since both cells
and spores have fairly constant widths (Table 1) the length of the spore is to change
in conformity to the length of the cell (from the abundant plasma of a long cell a
long spore develops). I succeeded in providing mathematical evidences for this

56 L. HAJDÚ
(SVÁB 19G7) : 16 parallel measurements offered evidences for a close linear correlation
(+0,6594 p

On the basis of HORTOBÁGYI'S algal catalogue (the state in November, 1973)
this species is new in the Hungarian Flora.
2. Oedogonium tyrolicum WITTEOCK. — Monoecious, in the filament the oogonia
are formed in ones. They are oval, with an oval aperture on their upper parts.
The oospores are round-elliptical, smooth-walled and do not fill the oogonium
completely. The antheridium is a little narrower than the filament. The apical
cell is bluntly rounded. The vegetative cells measure 75—113 by 14—25 ^m, the
oogonium is 48—53 pva wide and 73—104 pm long (MROZINSKA—WEBB 1969:
57—10 pm in length). The oospores are 45—52 pm wide, 52—10pm long (MROZLNS-
K A — W E B B 1. c: 40—47itm long). With the exception of the two data for length
nearly all taxonomic features well fit in with the specimens found (Figs. 6—8).
The species lived attached to the leaves of Najas minor.
On the basis of HORTOBÁGYI'S algal catalogue this species is new in the Hungarian
Flora.
3. Aphanochaete repens A BRAUN — It was found to grow as an epiphyton on
Oedogonium filaments. The 10 pm long and 7 pm wide cells formed straight on
occasion ramifying threads. On each cell a hair measuring up to 60 pm originates
which is onion-like thickened at its base.
4. Cladophora, glomerata (L.) KÜTZ. — The bulk of the algal mat on the bottom
of the pond was formed by this species. The apical cell is 45—60 ^um thick. The colony
is of acropetal organization (Fig 4). In culture it developed holdfasts as illustrated
in Fig. 5. There were numerous epiphytes, chiefly diatoms on the filaments.
5. Hydrodictyon reticulatum (L.)LAGERH. (= H. utriculatum ROTH and H. tenellum
ROTH) — This alga of peculiar construction is abundant in eutrophic waters
(KOL 1956, SÖRENSEN 1950).
Ecological data
The Városligeti-tó of Budapest is a temporary water. It is filled with tap water
yearly once from the watersystem and has neither out- or inflow. One third of the bottom
of the pond is covered with concrete, and from its other parts the sludge is reved by dredging.
In 1973 subsequent to dredging the pond was filled only later, on March 30.
By the time summer set in a thick algal web had developed on the bottom
of the pond, which consisted of the following three layers. Lowest down were
Hydrodictyon colonies embedded into a half-anaerobic deposit smelling of hydrogen
sulphide. This was covered by a thick, loose, coarse-textured Cladophora mat.
The algal mat was not of equal thickness everywhere and there were furrows to
some depth on its surface. The bright-green Spirogyra tufts were carried into this
furrows and by climbing on one another formed relatively massive conical heaps.
On August 10 the amount of algae found on a quadrate meter surface of the bottom
amounted to 1,8 kg fresh-weight resp. 0,48 kg dry weight in the average of three
samples.
Although in the pond Spirogyra was freuqent in the vegetative form, in the
conjugating form it was only seldom observed. The majority of them does not
reach the stage of zygospore formation. I examined a 2 m 2
spot covered with
Spirogyra in a medium advanced stage of conjugation for three weeks and found
the process to have progressed only in the case of a few filaments and not even $
then were spores produced. According to my observations proliferation occurs first
of all in places near to the water surface. This is evidenced also by the fact that
spore-formation is more frequent in case the water level of the pond decreases-

58 L. HAJDÚ
relatively fast. (The water of the pond oozed away into the ground due to an artifical
groundwater drainage in September. Under a 10 cm water layer a Spirogyra
mat of 5m 2
size was found where the process in 80 per cent of the cases reached the
stage of spore formation. From this mat we have abundant sample both dried and
formalin conserved one. At the time of spore formation there were numerous
epithytes on the Spirogyra threads (PANKOW 1961).
The algal mat of the pond was very uniform. Spots oi Ohara vulgaris L. and
Najas minor were only occasionally found. Ceratophyllum demersum was relatively
numerous. In August the algal mat becomes gradually separated from the bottom
and is drifted to and from on the water surface. This in our case was due to the circumstance
that the oxygen bubles produced by way of assimilation passed easily
through the coarse-textured, loose Cladophora mat yet some of them got captured
•among the small Hydrodictyon-nets below and among the Cladophores passing upwards
the little balloon rearranges the threads of the mat : from the bottom an empty,
gradually growing, Cladophora-walled cone passes upwards with Hydrodictyon
at its top. Reaching the surface the top of the cone opens and later on becomes
•completely detached from the bottom as a consequence of the smallest
motion.wave-
References
HORTOBÁGYI, T.: Catalogus et Iconographia Algarum Hungáriáé in Institutum Bot.
Univ. Agr. Gödöllő (status Nov. 1973, Manuscript).
KADLUBOWSKA, J. Z. (1972): Zygnemaceae in Flora Slodkovodna Polski PWN Krakow.
p. 1-431.
KOL, E. (1956) : Comparative algological and hydrobiological studies in rice fields in Hungary
- Acta Bot. Hung., 2: 309-363.
BANGER, S. (1934): Monographische Bearbeitung der Spirogyren mit besonderer Berücksichtigung
der Vorkriesungarisehen Verhältnisse — Folia Cryptogamica, 1: 1253 —
1306.
MROZINSKA - WEBB, T. (1969) : Oedogoniales in Flora Slodkovodna Polski- PWN Krakow,
p. 1-659.
PANKOW, H. (1961): Über die Ursachen des Fehlens von Epiphyten auf Zygnemalen. —
Arch. Protistenk., 105: 417-444.
ISOKAL, R. R. & SNEATH, P. II. A. (1963): Principles of Numerical Taxonomy. - Freeman
and Co., San Francisco — London, p. 1 — 359.
•SÖRENSEN, I. (1950): Studies in the Ecology of Hydrodictyon reticulatum (L.) Lagerh.
- Oikos, 2: 197-212.
SVÁB, J. (1967): Biometriai módszerek a mezőgazdasági kutatásban — Mezőgazd. Kiadó,
Budapest, p. 1 —498.
VAN DEN HOEK, C. (1963) : Revision of the European species of Cladophora — Leiden, E. J.
Brill, p. 1-248.
Author's address: Dr. L. HAJDU
Botanical Department of the
Hungarian Natural History Museum
H — 1146 Budapest, Vajdahunyadvár
Hungary