Russian dandelions
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Russian dandelion ( Taraxacum kok-saghyz ) |
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The Russian dandelion ( Taraxacum kok-saghyz , also Taraxacum koksaghyz ) is a species of the genus Dandelion (Taraxacum) ( Taraxacum ) in the sunflower family (Asteraceae). It is originally from Kazakhstan and western Xinjiang . This species is currently being intensively researched in order to obtain natural rubber .
description
Appearance and foliage leaf
The Russian dandelion is a perennial herbaceous plant that reaches heights of 4 to 15 cm. It contains a white milky juice in all parts . A tap root is formed.
The leaves stand together in a basal rosette. The leaf stalk is pale green and winged. The simple, bluish-greyish-green, more or less fleshy leaf blade is 3 to 7 (up to 10) cm long and 1.2 to 3 cm wide and narrow to broadly obscured. The leaf margin is serrated to regularly lobed to pinnate. The two or three, or rarely five, pairs of side lobes are broadly triangular. The leaf blade has at most a few spider-shaped hairs ( trichomes ) or is bald.
Inflorescence and flower
The flowering period in China extends from late spring to early summer. The light green to pink inflorescence stem has spider-shaped hairs and more or less towers over the leaves. The cup-shaped inflorescence has a diameter of 2 to 3 cm. The 8 to 13 outer bracts, which are not arranged in the shape of a roof tile, are light green, sometimes appearing violet in the light and are ovate to narrowly ovate. The outer bracts are shorter than the inner bracts with a length of 5.5 to 7 mm and a width of 1.2 to 2.2 (1 to 2.5) mm. They are slightly pressed to erect, the edge is whitish light green or membranous. The inner bracts are 8 to 12 mm long with a thin 1 to 2 mm long horn at the top. The ray-florets are light yellow, the inner ones are serrated yellow at the top. The scars are intense yellow.
fruit
With a length of 2.8 to 3.8 mm and a width of 0.7 to 0.9 mm, the light grayish straw-brown achenes gradually narrow to an almost cylindrical, cone-like shape. They are more or less densely thorn and are flattened conical with a 3 to 4.5 mm long beak. The white pappus has a length of 3.5 to 4.5 mm.
Chromosome number
The number of chromosomes is 2n = 16 with a diploid chromosome set.
Occurrence
The original homeland is Kazakhstan and western Xinjiang.
The Russian dandelion prefers sandy to loamy and clayey soils that are well-drained but moist. It can grow in acidic, neutral, and even highly alkaline soils. It grows both in partial shade and in full daylight.
Taxonomy
The first description of Taraxacum koksaghyz was in 1933 by Leonid Efimovic Rodin in Trudy Botanicheskogo Instituta Akademii Nauk SSS R. , Ser. 1, in: Flora i Sistematika Vysshikh Rastenii. Moscow & Leningrad , 1, pp. 187-189, Figures 1-10. A synonym for Taraxacum kok-saghyz Rodin is Taraxacum brevicorniculatum Korol.
The specific epithet koksaghyz is derived from the Turkic kok-sagiz , with the words kok meaning “root” and sagiz “rubber”.
use
The Russian dandelion was discovered in the Tian Shan Mountains in Kazakhstan in 1931 when a search was made for a native source of rubber in what was then the Soviet Union . In the 1930s, the German Rubber Research Association also examined, among other things, some plant species that could be cultivated in the temperate latitudes, including Taraxacum koksaghyz L.E. Rodin, and average rubber contents of 17% of their dry matter were reported in the roots. As early as 1941, 30% of Soviet rubber consumption was produced on 67,000 hectares. It has also been researched and cultivated in other countries, including in the German Empire under the Kok-Saghys project . In the 1942 set up in the Auschwitz concentration camp , by SS- Obersturmbannführer Dr. Joachim Caesar headed the research station for plant rubber , 150 to 250 forced laborers were employed. After the Second World War , however, it was soon ousted by Hevea brasiliensis , including in the Soviet Union. Only since the turn of the millennium has it been considered again as a substitute for rubber.
In the north of Germany, the cultivation of Taraxacum koksaghyz has recently experienced a renaissance.
Rubber substitute
Forgotten after the Second World War, the Russian dandelion has been regarded as a potential raw material plant for rubber for several years and has been researched in Europe and North America. The aim of the research is to obtain usable dandelion rubber from the Russian dandelion as an alternative to the natural rubber commonly used today from the milky sap of the rubber tree ( Hevea brasiliensis ) and synthetic rubber . The Russian dandelion provides 1 milliliter of rubber per plant. In addition, the short life cycle of six to eight months and the possibility of tissue cultures offer additional advantages over other potential rubber suppliers. The rubber particles extracted from the Russian dandelion are very similar to those from Hevea brasiliensis . They contain very pure poly ( cis -1,4-isoprene) with a high molecular mass.
Other uses
The main active ingredients are sesquiterpene lactone bitter substances (tetrahydroridentine B, taraxacolid-β- D -glucodide and others), a phenol carboxylic acid derivative (taraxoside), and triterpenes (taraxasterol and its derivatives) and inulin . This makes the Russian dandelion an interesting destination for the pharmaceutical industry.
literature
- Xuejun Ge, Jan Kirschner, Jan Štěpánek: Taraxacum : Taraxacum kok-saghyz , p. 312 - online with the same text as the printed work , In: Wu Zheng-Yi, Peter H. Raven & Deyuan Hong (editors): Flora of China. Volume 20–21 - Asteraceae , Science Press and Missouri Botanical Garden Press, Beijing and St. Louis, November 12, 2011. ISBN 978-1-935641-07-0 (Description and Distribution Section)
- Jan B. van Beilen, Yves Poirier: Guayule and Russian Dandelion as Alternative Sources of Natural Rubber. In: Critical Reviews in Biotechnology. Volume 27, No. 4, 2007, pp. 217-231: doi : 10.1080 / 07388550701775927 . (Usage section)
- RW Böhme: Cultivation and breeding of rubber and gutta-percha plants in the temperate zone. In: Z. f. Plant breeding Vol. 23, Issue 34, pp. 371-534, Berlin 1940 (section on use)
Individual evidence
- ↑ a b c d e f g Xuejun Ge, Jan Kirschner & Jan Štěpánek: Taraxacum : Taraxacum kok-saghyz , p. 312 - online with the same text as the printed work , In: Wu Zheng-Yi, Peter H. Raven & Deyuan Hong (editors ): Flora of China , Volume 20-21 - Asteraceae , Science Press and Missouri Botanical Garden Press, Beijing and St. Louis, 2011, ISBN 978-1-935641-07-0 .
- ↑ a b Kern, Timo: Funding example latex made from dandelions . Ed .: biotechnologie.de. 2011 ( online [accessed December 23, 2011]).
- ↑ Taraxacum koksaghyz at Plants For A Future .
- ↑ Taraxacum kok-saghyz at Tropicos.org. Missouri Botanical Garden, St. Louis.
- ↑ middleeastexplorer . ( Memento of the original from March 4, 2016 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. Retrieved December 24, 2011.
- ↑ a b c van Beilen JB, Poirier Y ,: Guayule and Russian Dandelion as Alternative Sources of Natural Rubber . In: Crit. Rev. Biotechnol. tape 27 , 2007, doi : 10.1080 / 07388550701775927 (free full text).
- ↑ Frankfurter Allgemeine Sonntagszeitung No. 18 of May 4, 2008, p. 67.
- ^ Ingo Uhlemann, Marie Eggert, Joachim Schiemann, Katja Thiele: On the re-cultivation of Taraxacum koksaghyz (Asteraceae) as a rubber supplier in Germany . In: Kochia . tape 12 , 2019, pp. 19-35 .
- ↑ T. Schmidt, M. Lenders, A. Hillebrand, N. van Deenen, O. Munt, R. Reichelt, W. Eisenreich, R. Fischer, D. Prüfer, CS Gronover: Characterization of rubber particles and rubber chain elongation in Taraxacum koksaghyz. In: BMC biochemistry. Volume 11, 2010, p. 11, doi : 10.1186 / 1471-2091-11-11 , PMID 20170509 , PMC 2836272 (free full text).
Web links
- Fraunhofer and Continental together bring dandelion rubber to the streets (press release at idw)