Laminariales

from Wikipedia, the free encyclopedia
Laminariales
Palm wrack (Laminaria hyperborea), illustration from Koehler's Medicinal Plants

Palm wrack ( Laminaria hyperborea ), illustration from Koehler's Medicinal Plants

Systematics
Domain : Eukaryotes (eukaryota)
without rank: Diaphoreticks
without rank: Sar
without rank: Stramenopiles (stramenopiles)
without rank: Brown algae (Phaeophyceae)
without rank: Laminariales
Scientific name
Laminariales
Mig.

The Laminariales are a taxon of brown algae whose members form kelp forests underwater in the clear, shallow sea . In German they, like multicellular red and green algae , are generally referred to as tang , several genera also with the word kelp, which was taken over from English . These include the giant kelp ( Macrocystis pyrifera ), which, together with the sporophytes, can reach a length of up to 60 meters.

In 2007 the Phycology Section of the German Botanical Society named the seaweed of the genus Laminaria the first alga of the year .

features

The Laminariales show a heteromorphic generation change : The sporophytes are handsome to very large, thallous algae (seaweed) . The gametophytes, on the other hand, consist of microscopic, branched cell threads. In female gametophytes, the vegetative cells are also significantly larger than in male ones, but their number is lower (up to single-celled female algae), so that one can speak of secondary sexual characteristics .

The large sporophyte of the Laminariales (macrothallus) has a thallous structure and consists of the rhizoid, cauloid and phylloid. The rhizoid is similar to the root of a plant. With the Laminariales it consists of so-called hapteren (claws) with the help of which the sporophyte attaches to stones. The cauloid (the stem axis in plants) forms a stem from which one or more leaf-like fronds ( phylloids ) extend. The term phylloid refers to the word phyllom , the scientific name for the leaf of the higher plants. At the end of the cauloids of some species there are gas bubbles, so-called pneumatocysts (also known as aerocysts), which provide buoyancy. In species of the genus Nereocystis of the Laminariaceae family , a single gas bubble forms on the cauloid, while several are found in the genus Macrocystis, which belongs to the same family . The sporophyte of the Laminariales has a conductive tissue.

growth

The growth of the gametophyte starts from the apical meristem cell. The sporophyte, on the other hand, has a very complex organized tissue, the intercalary growth of the cauloid is based on a divisible closing tissue ( meristem ), which is called the meristoderm in the laminariales. At the base of the phylloid there is another meristem, also on the surface of the rhizoids.

Differences to other brown algae

In contrast to the heteromorphic generation change of the Laminariales, an isomorphic generation change also occurs in other brown algae, e.g. B. in the Ectocarpales (genus Ectocarpus ) and in the Dictyotales (genus Dictyota ). In the genus Cutleria of the Cutleriales , in contrast to the Laminariales, the gametophyte is much more pronounced than the microscopic sporophyte. Representatives of the Fucales, on the other hand, can be described as diplonts . The sporophyte already forms the gametes, so there is no gametophyte.

Systematics

Palm wrack (Laminaria hyperborea)
Giant kelp ( Macrocystis pyrifera )
Nererocystis luetkeana
Sea palm ( Polstelsia palmaeformis )
Sugar kelp (Saccharina latissima)

The Laminariales were set up in 1909 by Walter Migula (In: Kryptogamen-Flora von Deutschland, Deutsch-Österreich und der Schweiz. Volume II. Algen. Part 2. Rhodophyceae, Phaeophyceae, Characeae. Pp. I-iv, 1-382, 122 (41 col.) Pls. Gera: Verlag Friedriech von Zezschwitz). It is divided into 34 genera and about 129 species (according to Guiry 2014).

use

Kombu , as laminariums are called in Japanese , is very common in Japanese cuisine . Russian cuisine also knows this as a salad-like side dish with oil dressing.

literature

Individual evidence

  1. ^ Section Phycology of the German Botanical Society: Seaweed Laminaria is Alga of the Year 2007 . Press release 2007.
  2. ↑ Textbook of botany for universities , 31st edition 1978, p. 584ff.

Web links

Commons : Category Laminariales  - Collection of images, videos and audio files