Pringlea antiscorbutica

Old plant on the Kerguelen, Rallier du Baty

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

Young plants superficially resemble the well-known carbon species with which the species is but only very distantly related. The leaves contain vitamin C, which is why they were used in the 19th century sailors in the Indian Ocean as food for the prevention of scurvy. In its distribution area of ​​Kerguelenkohl was formerly often by humans entrained other species, however, have almost everywhere out massively to its decline.

Features

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

The basal, roundish to ovate leaves of the rosette are together in the manner of a cabbage. They are blue - green, reach a length of about 29 centimeters and a width of up to 15.8 centimeters, in adult plants, the rosette of about 46 leaves is formed.

Between the leaves grow from the third or fourth year, three to five inflorescence axes up. The inflorescences are occasionally branched, it may persist for many years. An old plants up to 28 pieces could be found, including up to eight years old. The flowers are short-stalked, the four sepals are green, hairy and about 6 millimeters long. The four small petals are often incomplete or missing altogether, often in 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 style short. The large scars are round and papillose.

The flower is weak protogyn, the carpels are even before the stamens mature, in order to promote cross-pollination. The six stamens are shorter than the ovary in young flowers, mature they are, however, a third longer than the punch. The scars are ready to conceive, already before the stamens begin to grow. Only when the dust bag stand by the growth of stamens above the scars, they open up and pour the mature pollen.

The pods are zweikammerig dry during ripening and then open to release the numerous seeds. The seeds are up to four millimeters long, in contact with water they are slimy. Thus, the seeds are protected if they fall from the fruit in fresh or salt water and are carried away by this ( Hydrochorie ). The chromosome number is 2n = 24

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

Distribution and climate

The Kerguelenkohl is located on the Kerguelen, Crozet the Archipelago, Heard Island and the Prince Edward and Marion Islands and is thus endemic to the Kerguelen phytogeographic zone. All the islands are 1800-4800 miles away from inhabited continents between South Africa, Western Australia and Antarctica in the south of the Indian Ocean.

Characteristic of the islands is their location in the Roaring Forties, all year blowing strong winds from the west, causing unstable weather, rain and high seas and often become storms. The climate is cold - oceanic, on Heard Island, the southernmost island of the distribution area, the temperatures throughout the year at 1 ° C with 1,360 millimeters of precipitation at 276 rainy days per year. On the Kerguelen the annual average is 4.6 ° C (varying between 23 ° C and just above 0 ° C in summer and -5 to -14 ° C in winter ), and the precipitates at 674 millimeters per year, with a relative dryness in summer.

Ecology

The flora of the subantarctic islands is extremely poor in species. So come on the Kerguelen 29 plant species, even on Heard only 12 The Kerguelenkohl is specially adapted to the extreme conditions of the sub-Antarctic islands. The growth of the plants are places in the mountains and go up near the coast, where they are exposed to salty sea spray. This indirectly increases the salinity of the soil, however, after which the plants respond tolerant. Preferred locations are profound and fertilized by guano soils. The Kerguelenkohl grows mostly associated with Acaena magellanica, Azorella selago, on the coasts with Cotula plumosa.

Unlike most other cruciferous plants that are pollinated by insects, outweighs the Kerguelenkohl for lack of pollinators self-pollination ( autogamy ). This is due to that there is no native flying insects on the islands of its range due to the strong winds. A pollination by the wind would be theoretically possible, but is probably of only minor importance, since it not only high population densities weak winds and low humidity presupposes two factors that are rarely found in these latitudes.

The Kerguelenkohl is also the only host species of the sub-Antarctic islands endemic, wingless Stelzfliegenart, Calycopteryx mosleyi. Since it is the occurrence of Kerguelenkohls dependent, their stocks have declined significantly.

Endangering

The suspension of rabbit on the Kerguelen 1874 " proved to be a disaster for this sensitive and underdeveloped ecosystem " and led to a sharp decline of the local vegetation. In particular, the originally widespread and important for petrels nesting site plant community from the Kerguelenkohl and Azorella selago important since in the south of the main island and on nine other islands monotypic stands of Acaena magellanica. The Kerguelenkohl was pushed back through the rabbits in areas that are inaccessible for this and comes to the Kerguelen today only scattered on a few peninsulas ago. Mid-1990 began to plan the restoration of the original vegetation of the Kerguelen Islands, in test runs were previously able to be successfully eradicated on three small islands, the rabbits, by alluvial seeds of Kerguelenkohl settled then on again.

On Marion Iceland threaten the diamondback moth (Plutella xylostella ), gray mold (Botrytis cinerea ) and the screw - type Deroceras panormitanum the stocks. All these species have been introduced.

In more recent times, the global warming that meets relatively strong the sub-Antarctic islands, led to a notable increase in temperature and a decrease in rainfall. These changes have the decline in stocks of moisture- loving species, especially in already somewhat drier areas continued.

Was unharmed and is the type on Heard. She is the only one of the sub-Antarctic islands, on which there is no established animal or plant species. The changes brought about by climate change is here beneficial for the flora, as the glaciers that still occupy the largest part of the island retreat, and the habitable area of the plant is continuously larger.

Use

For the wedding of hunting whales, seals and penguins on the Kerguelen 1800-1870 the Kerguelenkohl was active there crews because of its activity against scurvy as " invaluable " vegetables. However, the use of Kerguelenkohl as food and Antiskorbutikum lost in the 19th century in importance.

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

Historical reports to the taste - as well as those occasional visitors later - attest to the Kerguelenkohl the " watery - tart flavor antiskorbutischer plants". The consistency of the raw leaves is described as " fluffy (like flannel) ," her taste as "strong and bitter [ ... ], similar to the strongest horseradish ". While from the cooking but the leaves have a water dark yellow coloring matter, the " disgusting " and a water change needed makes the food, then the leaves were then " stringy ", but would be edible. Cook wrote that the " essential oils would give a peculiar taste, which the majority of the officers as well as the crew had not been unaccommodating " was. From the U.S. Transit of Venus Expedition 1874-75 is reported that the leaves of the Kerguelenkohls of humans and animals were eaten " with pleasure ". Also, the rhizome is edible and has strong similarity in taste with horseradish on.

Recent studies attested the Kerguelenkohl in all respects utility as commercially viable vegetables both for its taste and direction as well as with respect to its nutritional value and konstatierten: " This vegetable has significant potential and deserves further investigation, including field trials on cool sites and toxicological studies. " Proves to be difficult However, commercial cultivation, since the plants are very susceptible to pests and diseases.

History and systematics

The type 1776 on the third voyage of Captain James Cook by ship's doctor William Anderson discovered on the Kerguelen, who erstbeschrieb 1785. Joseph Dalton Hooker, knowing their characteristics and placed it in a separate monotypic genus. The genus name honors Sir John Pringle, the then President of the Royal Society and a pioneer of military medicine, which by means of a - had tried " fermentation " theory intensively to combat scurvy - from today's perspective wrong. The Style epithet refers explicitly to the use as a remedy for scurvy.

Species and genus are performed within the family in the tribe Schizopetaleae, which was originally classified as relatively primitive, is understood but now derived as stronger. The species of the genus of the tendrils are considered closest related ( Sisymbrium ). Using the actual cabbage, brassicas, he is not related directly. The Kerguelenkohl is true at least for the Kerguelen as - together with Lyallia kerguelensis - the only remnant of the much more diverse Tertiary flora.

Evidence

• Agnes shear Man 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 falling on 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