Undaria Suringar, 1873

Holotype species: Undaria pinnatifida (Harvey) Suringar

Original publication and holotype designation: Suringar, W.F.R. (1873). Illustrationes des algues du Japon. Musée Botanique de Leide 1: 77-90, pls 26-33.

Description: Life history diplohaplontic with alternation of large sporophyte bearing unilocular meiosporangia with paraphyses (sori) and microscopic dioecious and oogamous, heteromorphous gametophytes (for detail, see Laminaria). Haploid chromosome number is 30 in U. pinnatifida and U. peterseniana (Migita 1967, Yabu et al.1988). Sporophyte annual, appearing in winter and disintegrating the following autumn. Sporophyte composed of holdfast with haptera, stipe, and blade. Meristematic region situated at transition zone between stipe and blade. Stipe compressed at base to flattened above, with wings (greatly expanded to narrow) which are more or less undulato-plicated and with sori or sterile. Blade linear to rounded or with pinnate lobes, with midrib or thickened fascia. Cryptostomata and dot-like mucilage glands present. Sori develop in summer on both surfaces of wings (sporophylls), or on both sides of midrib or fascia, or at the same time on sporophylls and blade. In culture, sori of U. pinnatifida are formed in longday conditions, probably induced by high water temperatures (Sanbonsuga and Hasegawa 1967). Zoospores of U. pinnatifida germinate between 13 and 24°C gametophytes grow well at 15-23°C (Saito 1956). Survival range of gamtophytes is -1 to 28°C (Akiyama 1965, tom Dieck 1993). Optimal temperatures for formation and growth of U. pinnatifida sporophytes is 10-20°C but at 5 and 25°C sporophytes are still formed (Akiyama 1965). U. undarioides seems to be more warm adapted with sporophytes stopping growth below 14°C (Segi and Kida 1958). Structure of sporophyte as in Laminaria composed of Photosynthetic meristoderm, parenchymatic cortex and central medulla. Crossing experiments between the Undaria spp. were successful up to the F1 sporophyte generation in all reciprocal crosses. Most crosses showed morphologically intermediate forms in the F1 generation and segregation of intermediate forms and progeny resembling the grandparents in the F2 generation. Hybrids between U. pinnatifida and U. undarioides only became mature and formed a F2 sporophyte generation (Saito 1972). A further study also revealed F2 hybrids for U. peterseniana female X U. pinnatifida male (Migita 1967). In U. pinnatifida parthenosporophytes with normal morphology may develop at low rates releasing only female determined zoospores when maturing (Fang and others 1982). Genus originally endemic to the northwestern Pacific, growing subtidally on rocks in warm-temperate waters of Japan (for detail: Saito 1972), Korea and China. Recently, U. pinnatifida was introduced to France, New Zealand and Tasmania, probably via oyster cultures and ships. Since then the species is expanding its distribution range (Floc'h and others 1991, Hay 1990, Sanderson and Barrett 1989). Genus of great economic importance as food source in Japan and Korea, especially U. pinnatifida (trade name: Wakame). Total annual yield from natural harvest and cultivation sites of Undaria spp. was about 130,000 tons fresh weight in 1967 (Saito 1975). Long-line culture started in the early 1960's and meanwhile production increased to about 30% of the wild harvest in Japan (Sanbonsuga 1984). For cultivation methods and propagation of Undaria see Saito (1975) and Jung (1988). In recent years, first progress in tissue culture, protoplast isolation and cryopreservation of U. pinnatifida was achieved (Arbault et al. 1990, Chen 1984, Shabao 1988, Tokuda & Kawashima 1988).

Information contributed by: E. C. Henry. The most recent alteration to this page was made on 2014-06-21 by M.D. Guiry.

Taxonomic status: This name is of an entity that is currently accepted taxonomically.

Most recent taxonomic treatment adopted: Silberfeld, T., Rousseau, F. & Reviers, B. de (2014). An updated classification of brown algae (Ochrophyta, Phaeophyceae). Cryptogamie Algologie 35(2): 117-156, 1 fig., 1 table.

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Some of the descriptions included in AlgaeBase were originally from the unpublished Encyclopedia of Algal Genera, organised in the 1990s by Dr Bruce Parker on behalf of the Phycological Society of America (PSA) and intended to be published in CD format. These AlgaeBase descriptions are now being continually updated, and each current contributor is identified above. The PSA and AlgaeBase warmly acknowledge the generosity of all past and present contributors and particularly the work of Dr Parker.

Descriptions of chrysophyte genera were subsequently published in J. Kristiansen & H.R. Preisig (eds.). 2001. Encyclopedia of Chrysophyte Genera. Bibliotheca Phycologica 110: 1-260.

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M.D. Guiry in Guiry, M.D. & Guiry, G.M. 21 June 2014. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. https://www.algaebase.org; searched on 19 July 2024

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