Kerguelenkohl

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Kerguelenkohl
Old plant on the Kerguelen, Rallier du Baty

Old plant on the Kerguelen, Rallier du Baty

Systematics
Rosids
Eurosiden II
Order : Cruciferous (Brassicales)
Family : Cruciferous vegetables (Brassicaceae)
Genre : Pringlea
Type : Kerguelenkohl
Scientific name of the  genus
Pringlea
W.Anderson ex Hook.f.
Scientific name of the  species
Pringlea antiscorbutica
R.Br. ex Hook.f.

The pringlea ( Pringlea antiscorbutica ) is a plant that only on some sub-Antarctic islands in the Indian Ocean is indigenous, including the eponymous Kerguelen . It is the only representative of its genus from the cruciferous family (Brassicaceae).

Young plants superficially resemble the well-known types of cabbage , to which the species is only very distantly related. The leaves contain vitamin C , which is why they were used by seafarers in the Indian Ocean as a food to prevent scurvy in the 19th century . The Kerguelenkohl was previously common in its range, but other species introduced by humans have led to its decline almost everywhere.

features

The Kerguelenkohl is a perennial , branched growing plant with up to one meter long and up to 10 centimeters thick above-ground shoot axes . These end in leaf rosettes that can reach a diameter of up to 80 centimeters. The shoot axes grow from 15 to 18 centimeters thick, semi-woody rhizomes that are filled with a spongy and fibrous substance.

The basal, round to egg-shaped leaves of the rosette stand together like a cabbage. They are blue-green, reach a length of around 29 centimeters and a width of up to 15.8 centimeters; in fully-grown plants, the rosette is formed from around 46 leaves.

From the third or fourth year, three to five inflorescence axes grow up between the leaves . The inflorescences are occasionally branched, they can persist for many years. Up to 28 plants were found on old plants, including up to eight years old. The flowers have a short stalk, the four sepals are green, hairy and around 6 millimeters long. The four small petals are often incomplete or missing completely, often even at the bud.

The stamens reach a length of eight millimeters, the anthers are up to two millimeters long. The hairy ovary are oblong-round, the pen short. The large scars are rounded and papilose .

Blooming plant with Acaena magellanica

The flower is weakly protogynous , so the carpels are ripe before the stamens in order to promote cross- pollination . The six stamens are shorter than the ovary in young flowers, but when ripe they are a third longer than the pistil . The scars are ready for conception even before the stamens begin to grow. Only when the anthers are above the stigma due to the growth of the stamens do they open and release the ripe pollen.

The pods are two-chambered, dry as they ripen and then open to reveal the numerous seeds . The seeds are up to four millimeters long and become slimy on contact with water . This protects the seeds if they fall from the fruit into fresh or salt water and are carried away by this ( hydrochory ). The number of chromosomes is 2n = 24.

The plants can reach an age of eight or more years; the individual populations are very variable in their size and the number of inflorescence axes.

Distribution and climate

Distribution of the Kerguelenkohls (red)

Kerguelen cabbage is native to the Kerguelen , the Crozet Archipelago , Heard and the Prince Edward and Marion Islands and is therefore endemic to the Kerguelen phytogeographic zone. All islands are 1,800 to 4,800 kilometers away from inhabited continents between South Africa, Western Australia and Antarctica in the south of the Indian Ocean .

Characteristic for the islands is their location in the Roaring Forties , strong winds blowing all year round from the west, which cause inconsistent weather, rain and high seas and often turn into storms. The climate here is cold-oceanic, on Heard, the southernmost island of the distribution area, the average annual temperatures are 1 ° C with 1360 millimeters of precipitation on 276 rainy days per year. On the Kerguelen the annual mean is 4.6 ° C (fluctuating between 23 ° C and just over 0 ° C in summer and −5 to −14 ° C in winter) and precipitation is 674 millimeters per year with a relative dryness in the Summer.

ecology

Population on the Île Mayès (Kerguelen)

The flora of the sub-Antarctic islands is extremely species-poor. On the Kerguelen there are 29 plant species, on Heard only 12. The Kerguelen cabbage is specially adapted to the extreme conditions of the sub-Antarctic islands. The plants grow in the mountains and reach the coast, where they are exposed to salty spray. This also indirectly increases the salt content of the soil, to which the plants, however, react tolerantly . Preferred locations are deep soils fertilized by guano . The Kerguelenkohl grows mostly together with Acaena magellanica , Azorella selago , on the coasts also with Cotula plumosa .

In contrast to most of the other cruciferous plants that are pollinated by insects, the kerguelen cabbage predominates due to the lack of pollinators, self-pollination (autogamy). This is due to the fact that there are no native flying insects on the islands in its range due to the strong winds . Pollination by the wind would be theoretically possible, but is of little importance since it requires weak winds and low humidity in addition to high population densities, two factors that are rarely found in these latitudes.

Kerguelen cabbage is also the only host species of a wingless stilt fly , Calycopteryx mosleyi, which is endemic to the sub-Antarctic islands . Since it is dependent on the occurrence of Kerguelenkohls, its stocks have also decreased significantly.

Danger

The release of rabbits on the Kerguelen in 1874 "turned out to be a disaster for this sensitive and underdeveloped ecosystem" and resulted in an extreme decline in the local vegetation. In particular, the originally widespread plant community of Kerguelenkohl and Azorella selago, which was important as a nesting site for petrels, has since given way to monotypical stocks of Acaena magellanica in the south of the main island and on nine other islands . The kerguelen cabbage was pushed back by the rabbits into areas that are inaccessible to them and is now only found scattered on the Kerguelen on a few peninsulas. In the mid-1990s, the planning of restoring the original vegetation of the Kerguelen began. In test runs, the rabbits had previously been successfully exterminated on three small islands, and the kerguelen cabbage settled again through alluvial seeds.

On Marion Island, the cockroach ( Plutella xylostella ), gray mold rot ( Botrytis cinerea ) and the snail species Deroceras panormitanum threaten the populations. All of these species were introduced.

In recent times global warming , which affects the sub-Antarctic islands relatively strongly, has led to a significant increase in temperature and a decrease in precipitation. These changes have driven the decline in populations of the moisture-loving species, especially in areas that are already somewhat drier.

The species on Heard was and is not endangered. It is the only one of the sub-Antarctic islands that has no introduced animal or plant species. The changes triggered by climate change are beneficial for the flora here, as the glaciers, which currently occupy most of the island, are retreating and the area habitable by the plants is continuously increasing.

use

At the height of the hunt for whales, seals and penguins on the Kerguelen between 1800 and 1870, the kerguelen cabbage was considered an “invaluable” vegetable by the ship's crews because of its anti- scurvy effect . The use of Kerguelenkohl as a food and anti-scorbutic, however, lost its importance in the 19th century.

Leaf rosette

Later studies confirmed the high vitamin C content, per 100 g it is 121 to 190 mg in the heart leaves (comparable to Brussels sprouts or parsley ), in the outer leaves 63 to 112 mg. The rhizomes also contain vitamin C, between 3 and 126 mg, depending on age.

Historical reports on the taste - as well as those of occasional later visitors - attest the kerguelenkohl the "watery-sour taste of anti-scorbut plants". The consistency of the raw leaves is described as "fluffy (like flannel )", their taste as "strong and bitter [...], similar to the strongest horseradish". During cooking, the leaves exude a substance that stains the water dark yellow, which makes the food “unsavory” and requires a water change, after which the leaves are then “fibrous” but become edible. Cook wrote that the "essential oils gave a peculiar taste which the majority of the officers as well as the crew were not unhealthy". It is reported from the US-American Venus Transit Expedition 1874-75 that the leaves of the Kerguelenkohl were eaten “with pleasure” by humans and animals. The rhizome is also edible and has a strong taste similar to horseradish .

Current studies have confirmed that Kerguelenkohl can be used as a commercially viable vegetable in every respect, both in terms of taste and nutritional value, and stated: "This vegetable has clear potential and deserves further studies, including field tests in cool locations and toxicological studies." commercial cultivation, however, as the plants are very susceptible to pests and diseases.

History and systematics

The species was discovered in 1776 on James Cook's third voyage to the Kerguelen by ship doctor William Anderson , who first described it in 1785 . Joseph Dalton Hooker recognized their peculiarities and placed them in a separate, monotypical genus. The generic name honors Sir John Pringle , the then President of the Royal Society and pioneer of military medicine, who had tried hard to combat scurvy by means of a "fermentation theory" that is wrong from today's perspective. The type epithet explicitly refers to its use as a remedy for scurvy.

Within the cruciferous family, the genus is classified in the tribe Thelypodieae , with the actual cabbage , the genus Brassica , the Kerguelenkohl is not directly related. The species probably developed in the late Miocene or early Pliocene from a predecessor species that was native to South America.

proof

  • Agnes Schermann-Legionnet, Francoise Hennion, Philippe Vernon, Anne Atlan: Breeding system of the subantarctic plant species Pringlea antiscorbutica R. Br. And search for potential insect pollinators in the Kerguelen Islands. In: Polar Biology. Berlin 30.2007, 1183-1193. ISSN  0722-4060
  • Irène Hummel, Frédéric Quemmerais, Gwenola Gouesbet, Abdelhak El Amrani, Yves Frenot, Françoise Hennion, Ivan Couée: Characterization of Environmental Stress Responses during Early Development of Pringlea antiscorbutica in the Field at Kerguelen. In: New Phytologist. Oxford 162.2004,3, 705-715. ISSN  0028-646X
  • J.-L. Chapuis, F. Hennion, V. Le Roux, J. Le Cuziat: Growth and reproduction of the endemic cruciferous species Pringlea antiscorbutica in Kerguelen Islands. In: Polar Biology. Berlin, 23.2000, 196-204. ISSN  0722-4060

Individual evidence

Most of the information in this article has been taken from the sources given under references; the following sources are also cited:

  1. ↑ SB Young, EK Schofield: Palynological evidence for the late glacial occurrence of Pringlea and Lyallia on Kerguelen Island , in: Rhodora, 75: 241, 1973, online
  2. ^ A b c John W. Thieret, Steven B. Young: Notes on Economic Plants - The Kerguelen-cabbage, Pringlea antiscorbutica (Brassicaceae) . In: Economic Botany, 42: 288-291, 1988
  3. ↑ Urania plant kingdom . Volume 3: Flowering Plants 1, Urania-Verlag, Leipzig 1991, page 60, ISBN 978-3-332-00367-3
  4. ↑ Edith R. Saunders: A Reversionary Character in the Stock (Matthiola Incana) and its Significance in regard to the Structure and Evolution of the Gynoecium in the Rhoeadales, the Orchidaceae, and other Families In: Annals of Botany 37: 463, footnote 1 , 1923
  5. ↑ F. Hennion, H. Couderc: Cytogenetical study of Pringlea antiscorbutica R. Br. And Ranunculus moseleyi Hook. f. from the Kerguelen Islands , in: Antarctic Science 4 (1): 57-58, 1992
  6. ↑ Frederick Ducane Godman, Osbert Salvin: Biologia Centrali-Americana: zoology, botany and archeology , 1: iv, 1879, Online
  7. ↑ David K. McAlpine: Review of the Australian stilt flies (Diptera: Micropezidae) with a phylogenetic analysis of the family In: Invertebrate Taxonomy, 1998, 12, p. 57
  8. ↑ "has proved a disaster for this sensitive, depauperate ecosystem" , J.-L. Chapuis et al. 2000, p. 196
  9. ^ FJ Kloppers: First Report of Botryotinia fuckeliana on Kerguelen Cabbage on the Sub-Antarctic Marion Island. In: Plant Disease 82 (6): 710, 1998, online
  10. ↑ Entry on the flora of Heard Island on the “Heard Island and McDonald Islands” website of the Australian Antarctic Division ( Memento from February 9, 2008 in the Internet Archive )
  11. ^ J. Lindley, T. Moore: The Treasury of Botany , 1876, quoted from: John W. Thieret, Steven B. Young: Notes on Economic Plants - The Kerguelen-cabbage, Pringlea antiscorbutica (Brassicaceae) . In: Economic Botany, 42: 288-291, 1988
  12. ↑ HH Hatt: Vitamin C content of an old antiscorbutic: The Kerguelen cabbage. , Nature [London], 164: 1081-82, 1949, cited in: Journal for Food Research and Research, Vol. 94 (6): 432-436, 1952
  13. ^ A b J. Cook, J. King: A voyage to the Pacific Ocean , 1784, quoted from: John W. Thieret, Steven B. Young: Notes on Economic Plants - The Kerguelen-cabbage, Pringlea antiscorbutica (Brassicaceae) . In: Economic Botany, 42: 288-291, 1988
  14. ↑ a b c S.B. Young: Vascular Flora of the Kerguelen Islands. In: Antarc. J., 6 (4): 110-111, quoted from: John W. Thieret, Steven B. Young: Notes on Economic Plants - The Kerguelen-cabbage, Pringlea antiscorbutica (Brassicaceae) . In: Economic Botany, 42: 288-291, 1988
  15. ^ RR Du Baty: Fifteen Thousand Miles in a Ketch. , London, 1911, quoted from: John W. Thieret, Steven B. Young: Notes on Economic Plants - The Kerguelen-cabbage, Pringlea antiscorbutica (Brassicaceae) . In: Economic Botany, 42: 288-291, 1988
  16. ^ Jerome Henry Kidder: Contributions to the Natural History of Kerguelen Island in Connection with the United States Transit-of-Venus-Expedition 1874-75. In: Bull. US Nat. Museum, 3: 1-122, quoted from: John W. Thieret, Steven B. Young: Notes on Economic Plants - The Kerguelen-cabbage, Pringlea antiscorbutica (Brassicaceae) . In: Economic Botany, 42: 288-291, 1988
  17. ^ "This crop has significant potential and deserves further investigation, including field growth trials in a cool location, and toxicological studies." , Iain Dawson: New Salad & Vegetable Crops From Australia's sub-Antarctic Islands , Rural Industries Research and Development Corporation, 1998 , ISBN 0-642-57857-5 , p. Vii, Online (DOC) ( Memento of October 26, 2007 in the Internet Archive )
  18. ^ Iain Dawson: New Salad & Vegetable Crops From Australia's sub-Antarctic Islands , Rural Industries Research and Development Corporation, 1998, ISBN 0-642-57857-5 , Online (DOC) ( Memento of October 26, 2007 in the Internet Archive )
  19. ↑ sciencedirect.com: Phylogeny and colonization history of Pringlea antiscorbutica (Brassicaceae), an emblematic endemic from the South Indian Ocean Province - ScienceDirect , accessed August 26, 2017

Web links

Commons : Kerguelenkohl ( Pringlea antiscorbutica )  - album with pictures, videos and audio files
This article was added to the list of excellent articles on April 26, 2008 in this version .