Undaria Suringar, 1873: 77
Classification:
Empire Eukaryota
Kingdom Chromista
Subkingdom Chromobiota
Infrakingdom Heterokonta
Phylum Heterokontophyta
Class Phaeophyceae
Order Laminariales
Family Alariaceae
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, Plates 26-33.
Taxonomic status: currently recognized as a distinct genus.
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).
NCBI Nucleotide Sequences
As of 2 June 2009, nucleotide sequence data are available at http://www.ncbi.nlm.nih.gov/Genbank for 180 samples identified as Undaria. Taxonomic identifications of these samples to genus (or species) levels unaccompanied by explicit indication of voucher specimens may not be verifiable on morphological/anatomical grounds and consequently be of little or no taxonomic value, as noted by Harvey et al. 2009.
Numbers of names and species: There are 13 species names in the database at present, of which 3 have been flagged as currently accepted taxonomically.
Names: ('C' indicates a name that is currently accepted taxonomically; 'S' a homotypic or heterotypic synonym; 'U' indicates a name of uncertain taxonomic status, but which has been subjected to some verification nomenclaturally; 'P' indicates a preliminary AlgaeBase entry that has not been subjected to any kind of verification. For more information on a species click on it to activate a link to the Species database):
Undaria crenata Y.-P. Lee & J.T. Yoon C
Undaria distans Miyabe & Okamura P
Undaria peterseniana (Kjellmann) Okamura S
Undaria pinnatifida f. elliptica Suringar P
Undaria pinnatifida f. typica Yendo P
Undaria pinnatifida f. narutensis Yendo P
Undaria pinnatifida f. distans (Miyabe & Okamura) Yendo P
Undaria pinnatifida var. distans Miyabe & Okamura P
Undaria pinnatifida (Harvey) Suringar C - type
Undaria pinnatifida var. elongata Suringar C
Undaria pinnatifida var. vulgaris Suringar C
Undaria pinnatifida f. subflabellata Suringar P
Undaria undarioides (Yendo) Okamura C
Information contributed by: E. C. Henry. The most recent alteration to this page was made on 28 Aug 2006 by M.D. Guiry.
Contributors
Many 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
and intended to be published in CD format.
The descriptions are being continually updated, however, and each current contributor is identified above.
The PSA and AlgaeBase warmly acknowledge the generosity of all past and present
contributors and of Dr Parker.
