Macrocystis ( lat. Macrocystis ) - a genus of brown algae from the kelp family. It includes the largest known algae, exceeding a length of 45 meters [2] . Individual specimens live up to 8-10 years, although algae usually have a shorter life. Used in aquaculture . They live in the southern hemisphere. They grow on rocky and rocky soils at a depth of 20-30 m. [3]
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Macrocystis pyrifera ( L. ) C. Agardh, 1820 [1] | |||||||||||||||||
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Content
Short Description
In representatives of the genus, the thallus is attached to the ground with rhizoids . The trunk has several long branches, on which there are a large number of annual leaf blades 1 m long and 20 cm wide with air bubbles at the base. The plant itself is perennial, but its branches with leaf-shaped plates are annual. Sporangia are formed on the lower sporophyll plates. The life cycle , the alternation of heteromorphic gametophyte and sporophyte , is similar to the life cycle of other brown algae. [3] There are different opinions regarding the length of macrocystis. If you take fresh sources, then in a review of the English botanist G. Prescott it is indicated: from 60 to 213 meters.
Appearance
Macrocystis looks like a garland of flags of irregular shape or the tail of a kite, humiliated with rags. Macrocystis tightly attaches to the ground or rocks with rhizoids, which serve as algae like roots. In a big storm, a piece of stone with macrocystis can come off a cliff, but a macrocystis can never come off a stone.
Macrocystis has the shape of a stem, first rising up, and then at the very surface of the water turning and going horizontally in the direction of the sea current. Thallus up to 45 m long (weight up to 150 kg) with rhizoids and leaf-shaped plates, with air bubbles supporting branches and plates near the surface. X rays penetrating to great depths. A long thin trunk carries numerous plates. The apical plate separates the new plates by oblique tears on one side. The base of the plates is pear-shaped swollen, contain a gas bubble. Due to this and the length of the branches, the upper part of the thallus floats at the surface of the water [4] . The growth of thallus occurs due to insertion meristems located between the stem and the plates.
Tall is complexly organized, has a crust, unpainted intermediate layer and core. The core contains large sieve tubes , providing transport of organic substances [5] . Substances move from actively photosynthetic parts of thallus to rhizoids and actively growing apex; their transport speed can reach 78 cm per hour. The structure of sieve tubes in macrocystis is different than in flowering plants; they lack satellite cells , but have many mitochondria [6] .
Growing
Due to the possibility of undermining the natural resources of algae, scientists are exploring the possibilities of growing macrocystis, namely pear-shaped macrocystis ( Macrocystis pyrifera ) on plantations. Since this algae is quickly restored, it is possible to collect up to 3 crops per year. Experiments on its cultivation have already been conducted in the USA, France and some other states. In California, pear-shaped macrocystis is already grown on marine farms as a food product, as a fertilizer, as an energy raw material (for gas and other types of fuel). Macrocystis is also used to obtain salts of alginic acid , which are used in the pulp and paper, perfumery, pharmaceutical, canning industries, as well as in metallurgy, electric welding and the production of building materials, and other chemical products.
Growing Method
When growing macrocystis, seedlings are strengthened on a grid of artificial fibers and immersed to a depth of 12-24 m. To enrich surface waters with biogens and improve algae growth, it is necessary to raise deep waters enriched with biogenes in the upper horizons. About 1 thousand plants are placed on an area of 1 ha, which produce 300-500 tons of wet weight per year. Algae is collected from special vessels that cut and collect the upper parts of plants. [3]
Significance in nature
Charles Darwin , studying this algae off the coast of South America, came to the conclusion that its “forests” support the existence of a much larger number of species than any other plant on Earth. Macrocystis is especially important for sea urchins, mollusks and fish. Also, forests of macrocystis are a haven for an endangered species - sea otters . Sea otters build their own algae bedrooms and prey on the sea urchins that live in their thickets.
See also
- Algae forest
- Aquaculture
- Kelp
- Fucus
Notes
- ↑ Gender Macrocystis information in the Index Nominum Genericorum database of the International Plant Taxonomy Association (IAPT) .
- ↑ Zinger, 1951 , p. 28.
- ↑ 1 2 3 Moses and others, 1985 .
- ↑ Belyakova, 2006 , p. 136.
- ↑ Belyakova, 2006 , p. 134-135.
- ↑ Lee, 2008 , p. 451.
Literature
- Belyakova G.A. Algae and mushrooms // Botany: in 4 vol. / Belyakova G. A., Dyakov Yu. T., Tarasov K. L. - M .: Publishing Center "Academy", 2006. - V. 2. - 320 p. - 3000 copies. - ISBN 5-7695-2750-1 .
- Zinger A.V. Entertaining botany. - 4. - M .: "Soviet Science", 1951. - 293 p. - 5,000 copies.
- P. A. Moiseev, A. F. Karpevich, O. D. Romantseva, and others. Marine aquaculture. - M .: "Agropromizdat", 1985.
- Ch. ed. M.S. Gilyarov; Editorial: A. A. Babaev, G. G. Vinberg, G. A. Zavarzin and others. Biological encyclopedic dictionary. - 2nd ed., Rev. - M .: “Owls. Encyclopedia ", 1986.
- Lee, RE Phycology, 4th edition. - Cambridge: Cambridge University Press, 2008 .-- 547 p. - ISBN 9780521682770 .
- M.M.Gollerbach, A.M. Matvienko et al. Plant life. - Enlightenment, 1977 .-- T. 3.
Link
- Algaebase: Macrocystis C. Agardh, 1820: 46
- IBM Museum FEB RAS: Giants of the underwater world
- Genus Macrocystis (English) in the World Register of Marine Species .
- Macrocystis
- Monterrey Underwater Forests (link not available)
- From seaweed to sea otter (inaccessible link)
- Brown algae (inaccessible link)