Laminaria

Palmentang ( Laminaria hyperborea ), stranded at Helgoland

Laminaria is a brown algae genus belonging to the order Laminariales. The species forms extensive Tangwälder on the coasts of North and South Atlantic and North Pacific. They are used commercially for the production of alginate. The Phycology Section of the German Botanical Society has named the genus Laminaria Algae to the first of the year in 2007.

• 7.1 Notes and references

Description

Features

The Laminaria sporophytes are about a foot tall, perennial seaweeds, which can reach an age of two to 18 years. They are divided into a holdfast ( rhizoid ), a stem ( Cauloid ) and a sheet-like surface ( Phylloid ). The adhesive organ is usually branched, rare disc-shaped (with Laminaria solidungula and L. yezoensis ) or rhizome ( at sinclairii L. and L. rodriguezii ). The circular cross-section or flattened stem can be internally meets with Mark or hollow. In some species in the stem growth rings can be seen. The Phylloid is either margin entire and unlobed ( section simplices ), or it has a distinct central strand ( Fasciatae section ), or is incomplete in finger-like segments divided ( Section digital markings ). The leaf surface is usually smooth, sometimes with beulig - blistered or kräuseliger surface, and has neither a midrib or longitudinal ribs.

Deciduous

The leaf surface is renewed every year, from the bottom up. Stored in the old deciduous reserve materials are transferred into the growth zone at the transition to the head this early in the winter. With increasing light grows there in the spring, a new Phylloid approach, where the last year's leaf initially seated. In some species, the old leaf is repelled as a whole, in others it degenerates gradually at the ends.

Tissue types

Laminaria sporophytes have various differentiated tissues: a central marrow (missing in the holdfast ), a parenchymatous cortex and the outer Meristoderm that is both photosynthetically active as well as the function of an educational tissue ( meristem ) has. In the real Mark line paths run ( sieve tubes ), in which the products of photosynthesis are transported. In the bark of the stem and Phylloid networked mucus channels occur, which lead in some species secretory cells on the surface.

Chromosome number

The chromosome number is n = 22 to n = 31

Development cycle

Laminaria is a generational change with two very different generations. The visible is the diploid sporophyte Tang. In the fall and winter of Phylloids at irregular darker spots ( sori ) are formed the tubular sporangia on both sides, in which will result in 32 mobile zoospores by meiosis. These possess a single plastid and have neither eyes nor spot a swelling at the Scourge.

The zoospores constitute and grow to microscopic haploid gametophyte approach, consisting of a few cells or branched hyphae. The formation of the gametes is triggered by blue light. Too high or too low temperatures, nutrient or iron deficiency, however, prevent the gamete. The male gametophyte form at the ends of branches tufts of colorless, unicellular antheridia, each releasing a single zweigeißeliges spermatozoid. In the female gametophyte, each cell can develop into a single-celled oogonium and form a single egg ( with rudimentary scourge residues). The oocyte initially adheres to the oogonium, and is usually released in the first 30 minutes after dark. The eggs differ simultaneously from the pheromone Lamoxiren, which attracts the sperm from the antheridia to the egg cells. After fertilization, the zygote sets and germinates into a young sporophyte.

The young plants are fertile for the first time with two or three years.

The life cycle of Laminaria is strongly influenced by the seasons. The time with the strongest growth in the spring. The sori occur in most species, however, in autumn and winter, triggered by the shorter day length and falling temperatures. Only a few species ( kelp Laminaria digitata =, L. ochroleuca and the short-lived rodriguezii L. and L. ephemera ) are fertile in summer.

Ecology

The Laminaria species have an important function in the ecosystem of Tangwälder because they offer many types of algae, animals and micro-organisms a habitat. Some of the microorganisms solve algae from diseases and damage the kelp, others protect the surface against rot or toxins or growth-promoting effect. Some microscopic algae live as endophytes within the kelp, for example Laminariocolax and Laminarionema. On the stems often grow numerous epiphytic algae, especially red algae. Many epiphytic animals live on the kelp, a special species richness shows the holdfast. Other hand, very high numbers of individuals were found on the stems, in part, to more than 7,000 individuals occur on a single laminaria stem. The Phylloid is mainly covered by the bryozoans Membranipora membranous.

Among the species that feed on kelp, the sea urchins have the strongest influence. In particular, sea urchins of the genus Strongylocentrotus, which have multiplied en masse after overfishing can erode all Tangwälder and completely destroy, so that all that remains is the bare ground.

Occurrence

The genus Laminaria is mainly in the cool - temperate water of the North Pacific, North Atlantic Ocean spread (also in North Sea, Baltic Sea and Mediterranean Sea ) and the South Atlantic. You lack in western South America, Australia and Antarctica. After molecular genetic studies is suspected that the species in the Atlantic and Pacific have separated before 15 to 19 million years ago.

Laminaria grows on rocky ground in the sublittoral zone, where it forms extensive Tangwälder. You can advance from the low water line to an ocean depth, is available in at least 1 % of the light. Therefore, their maximum depth of the transparency of the water is dependent. In the murky waters of the North Sea, the Palmentang ( Laminaria hyperborea ) is limited to a depth of up to 8 meters. The lowest incidence to 95 meters in clear water Laminaria ochroleuca reach and Laminaria Laminaria brasiliensis rodriguezii in the Mediterranean and off the coast of Brazil.

System

The genus Laminaria was erected in 1813 by John Vincent Felix Lamouroux (In:. Essai sur les genres de la famille the thalassiophytes non Articulees Annales du Muséum d' Histoire Naturelle, Paris 20: p 40). As type species Laminaria digitata was (Hudson ) JVLamouroux determined ( lectotype ).

The genus Laminaria belongs to the family Laminariaceae within the order of Laminariales. Guiry in AlgaeBase (2012 ) lists 24 types accepted:

• Laminaria abyssalis ABJoly & ECOliveira, S Atlantic: in the South Atlantic ( deep water off Brazil )
• Laminaria agardhii Kjellman: the Northwest Atlantic (Canada)
• Laminaria appressirhiza JEPetrov & VBVozzhinskaya: in the Pacific Northwest ( Sea of ​​Okhotsk )
• Laminaria brasiliensis ABJoly & ECOliveira: in the South Atlantic ( deep water off Brazil )
• Laminaria bullata Kjellman: in the North Pacific ( Bering Sea)
• Laminaria complanata ( Setchell & NLGardner ) Münscher: in the Northeast Pacific ( limited to Washington and British Columbia)
• Laminaria EYDawson cordata: in the North Pacific (California )
• Kelp ( Laminaria digitata (Hudson ) JVLamouroux ): in the North Atlantic, North Sea and Baltic Sea
• Laminaria ephemera Setchell: in the Northeast Pacific
• Laminaria farlowii Setchell: in the Northeast Pacific
• Palmentang ( Laminaria hyperborea ( Gunnerus ) Foslie ): North-East Atlantic, North Sea and Baltic Sea
• Laminaria inclinatorhiza JEPetrov & VBVozzhinskaya: in the Pacific Northwest ( Sea of ​​Okhotsk )
• Laminaria longipes Bory de Saint -Vincent: in the Northeast Pacific
• Laminaria nigripes J.Agardh: in the North Atlantic (Arctic)
• Laminaria ochroleuca Bachelot de la Pylaie: Northeast Atlantic and Mediterranean
• Laminaria pallida Greville: in the South Atlantic
• Laminaria Platymeris Bachelot de la Pylaie: the Northwest Atlantic (Maine, Massachusetts, Newfoundland)
• Laminaria rodriguezii Bornet: in the Mediterranean
• Laminaria ruprechtii ( Areschoug ) Setchell
• Laminaria setchellii PCSilva: in the Northeast Pacific
• Laminaria sinclairii ( Harvey ex JDHooker & Harvey ) Farlow, Anderson & Eaton: in the Northeast Pacific
• Laminaria solidungula J.Agardh: in the North Atlantic (Arctic)
• Laminaria yezoensis Miyabe: in the North Pacific

Numerous earlier counted Laminaria species (L. angustata, L. cichorioides, L. coriacea, L. dentigera, L. diabolica, L. groenlandica, L. japonica = Japanese kelp, L. longicruris, L. longipedalis, L. longissima, L. ochotensis, L. religiosa, L. saccharina and L. yendoana = sugar kelp ) were separated according to molecular genetic studies in 2006 as a separate genus saccharina.

Ingredients

The Laminaria species accumulate iodine to 30.000fachen the content in seawater. Thus, they are of all creatures the most iodine -accumulate. The iodine content of kelp ( Laminaria digitata ) may be 0.25 to 5 % of dry matter.

And the metals copper, manganese and iron are used as enriched and trace elements for the activation of enzymes, or for electron transport during photosynthesis. The highest concentrations were found in the holdfast.

In the cell walls to find the phycocolloids alginate and fucoidan. As memory Laminaran carbohydrates and mannitol occur.

Use

Laminaria species have great economic importance as a supplier of alginate. In Europe, natural resources are harvested to most. In 2005, a production of Norway stated by 154,000 t ( Laminaria hyperborea ) and France about 75,000 t ( Laminaria digitata especially ).

Other ingredients from kelp are used in many applications, such as cosmetics, food supplements, as a remedy, as an additive to animal feed or as fertilizer.

In addition, kelp can be used, or to reduce the erosion of coasts bioremediation ( bioremediation ) for pollution or eutrophication. Even as a bioreactor in molecular biotechnology or as a renewable resource ( fuel substitute ) they can be used.

Swell

• Michael D. Guiry, GM Guiry: Laminaria - In: AlgaeBase - World -wide electronic publication, National University of Ireland, Galway, accessed March 28, 2012 (Sections description, tissue types, chromosome number, development, systematics)
• Inka Bartsch, Christian Wiencke, Kai Bischof, Cornelia M. Buchholz, Bela H. Buck, Anja Eggert, Peter Fire Arrow, Dieter Hanelt, Sabine Jacobsen, Rolf Karez, Ulf Karsten, Markus Molis, Michael Y. Roleda, Hendrik Schubert, Schumann Rhena, Klaus Valentin, Florian Weinberger & Jutta Wiese: The genus Laminaria sensu lato: recent insights and Developments. In: European Journal of Phycology, 43:1, 2008, pp. 1-86 Full text online ( sections ingredients, ecology, resources, utilization )