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15(1): Cryptogams: Algae

Acetabularia major G. Martens

Preuss. Exped. Ost-As., Tange: 25, pl. 4, fig. 3 (1868).

POLYPHYSACEAE

2n = unknown

Acetabularia crenulata J.V. Lamour. var. major Sond. (1871), Acetabularia denudata Zanardini (1878), Acetabularia gigas Solms (1895).

Mermaid's wine glass (En). Indonesia: gembur batu, keji beling, pecah beling (Javanese, Sundanese). Philippines: payong-payong.

Acetabularia major is found in the Indian Ocean from Sri Lanka and in the Pacific Ocean from Melanesia, Taiwan and islands in the Torres Strait. In South-East Asia it is known from Thailand (Gulf), Peninsular Malaysia, Indonesia (West Java, Timor, Irian Jaya) and the Philippines.

Acetabularia major is used on the northern coast of Java as a medicine against stones in the gall-bladder, in the kidney or in the urine bladder. This is probably due to the ability of the rhizoids of the alga to secrete acids. In Indonesia (mainly West Java), Acetabularia major is also used as a laxative. Other Acetabularia spp. may also be used in the same way. Some of the unicellular, uninucleate green algae of the genus Acetabularia J.V. Lamour. have been used extensively for research in morphogenetics, physiology, molecular biology and cell biology.

Acetabularia major is not harvested or cultivated for commercial use. It is, however, possible to raise it in laboratory culture.

CaCO₃ is present in Acetabularia major in the form of aragonite (orthorhombic). No research has yet been done on the role of this alga in destroying intestinal stones. The vegetative cell walls of Acetabularia major partially consist of crystalline mannan as the skeletal component, but the gametangial cysts have cellulosic walls.

Thalli erect, moderately calcified, stalk slender, 2—20 cm tall, cap 10—20 mm in diameter, made up of 63—83 long slender rays, joined by calcification; tip of each ray ending in an entire, slightly emarginate or somewhat rounded margin; side walls with notches, giving them a streaky pattern. Corona superior (inside the cap) with segments 230—250 µm long, bearing (6—)8(—9) hair scars, often arranged in uniseriate rows; corona inferior (below the cap) with segments 265—280 µm long, ending in a rounded, truncate or emarginate margin. Life cycle diplontic. Gametangial cysts inside the cap rays oval, 119—129 µm x 89—109 µm, or spherical, 98—115 µm in diameter. Each cap ray containing about 100 cysts.

The adult form of the perennial thalli of Acetabularia major is composed of three portions: rhizoid, stalk and cap. Following conjugation of the haploid isogametes, the zygote (50 µm) gives rise to a rhizoid, which contains a single large nucleus, and an elongating stalk which ultimately terminates its growth (after 3—4 months) by the differentiation of a species-specific cap (about 1 cm in diameter) at the tip. At maturity the cap is subdivided into many rays, each of which is functionally a gametangium. At this time the large (150 µm) nucleus divides by mitosis into thousands of secondary nuclei. The nuclei migrate through the stalk into the rays of the cap where they form cysts. The cysts are set free when the cap degenerates and ultimately give rise, after meiosis of each secondary nucleus and many mitotic divisions, to numerous motile isogametes.

Acetabularia major is the largest species in Acetabularia. Acetabularia major var. gigas Solms (syn. Acetabularia gigas) is up to 25 cm long. The cap of this variety is composed of 70—80 sporangial rays and can reach a diameter of 30 mm. The corona superior is 300—400 µm long, while each segment bears 8—10 hair scars.

Acetabularia major is usually solitary and grows on hard objects like dead coral on moderately wave-washed habitats near shore, on hard substrates in sheltered sand flats with seagrasses and between large seagrasses. The very large specimens of var. gigas have never been found in their natural habitat, but only washed ashore.

Acetabularia major is not grown in phycoculture.

Acetabularia major, being a single-celled marine alga containing one nucleus, is capable of completing its life cycle in laboratory culture within 4—5 months, while in nature it takes at least a year.

Acetabularia major is collected by hand.

Acetabularia major can be sun-dried.

Acetabularia major will probably remain a traditional medicine in Java. It has to be tested for effectiveness. The thin calcareous tubes formed by this alga might be suitable for use in surgery, as a temporary substitute for skeletal elements, etc.

Berger, S. & Kaever, M.J., 1992. Dasycladales: an illustrated monograph of a fascinating algal order. Georg Thieme Verlag, Stuttgart, Germany. 247 pp.
Mariscal, R.N., 1974. Experimental marine biology. Academic Press, New York, United States. pp. 316—317.
Trono Jr, G.C. & Santiago, A.E., 1978. Notes on the genus Acetabularia (Chlorophyta) in the Philippines. Kalikasan 7(1): 77—90.
Valet, G., 1969. Contribution à l'étude de Dasycladales, 2. Cytologie et réproduction, 3. Révision systématique [Contribution to the study of Dasycladales, 2. Cytology and reproduction, 3. Systematic revision]. Nova Hedwigia 17: 551—644.

P.Y. van Aalderen-Zen

Van Aalderen-Zen, P.Y., 2001. Acetabularia major G. Martens. In: Prud'homme van Reine, W.F. and Trono Jr, G.C. (Editors): Plant Resources of South-East Asia No 15(1): Cryptogams: Algae. PROSEA Foundation, Bogor, Indonesia. Database record: prota4u.org/prosea