Water pepper

Water pepper
	Water pepper ( Persicaria hydropiper )
Systematics
	Eudicotyledons
	Nuclear eudicotyledons
Order :	Clove-like (Caryophyllales)
Family :	Knotweed family (Polygonaceae)
Genre :	Knot oak ( Persicaria )
Type :	Water pepper
Scientific name
	Persicaria hydropiper
	( L. ) Delarbre

Water pepper ( Persicaria hydropiper ), also called flea pepper , pepper knotweed , pepper cabbage or hot herb , is a species of knotweed ( Persicaria ). The sharp-tasting leaves and seeds are sometimes used as a spice.

description

Illustration from Flora Batava , Volume 6

Water pepper habit

Illustration from 1832

Appearance and Roots

The water pepper is an annual herbaceous plant . It germinates between April and May and dies from drought or at the latest with the first frost. The stem is erect, ascending or lying and green, often with a red ring after each knot . Branches grow out of the basal leaf axils. During aging ( senescence ) the whole stem turns reddish from bottom to top. It is bald or slightly hairy . The plant reaches heights of growth between 75 and 90 centimeters in a good location, in barren locations it remains between ten and 15 centimeters small.

The root system is heterogeneous and consists of a maximum ten centimeter long, vertically downwardly growing, often twisted main root and lateral roots branching off from it. If the lower part of the plant is covered with substrate, adventitious roots will grow out of the nodes . Mycorrhizae are not known.

leaf

The alternate leaves are divided into a petiole and a leaf blade. The leaf stalks are 1 to 8 millimeters in length; between 3 and 12 inches long and 0.8 to 2 inches wide. They are usually spotted brown on both sides, heaped near the midrib. Their shape is lanceolate, wedge-shaped at the base, ciliate on the edge and with a sharp point. The leaves are glabrous or slightly hairy on both sides and not glandular. The ochrea (stipple sheaths) is usually hairy with very fine eyelashes and occasionally glandular. As with the stem, the leaves turn reddish during senescence. The stomata are found almost exclusively on the underside of the leaf.

Inflorescence, flower and fruit

The flowering period extends from May to October, but the main flowering period is from June to September. The terminal, often pendulous, large, loose, spike-like inflorescence is 3 to 8 inches long. Smaller inflorescences arise from the axilla of a small bract at each node, those of the lower nodes are very inconspicuous and cleistogamous ( self-pollinating in closed flowers). These bracts are always shorter than the inflorescence axes. The Ochreolae (stipple sheath of the bracts) is fringed, hairless or slightly hairy and glandular.

The flower stalks are 0.5 to 1.25 mm long. The small, hermaphrodite flowers are 1.0 to 2.0 mm in diameter. The three, four or five green, at the tip somewhat white or reddish bloom bracts are densely covered with yellowish to brownish glands. The usually six or four, less often five or eight stamens have pink to red anthers . There are two or three styles in each flower .

The flower formula is: ${\ displaystyle \ star P _ {(4-5)} \; A_ {4-8} \; G _ {\ underline {(3)}}}$

About 2.5 to 4 millimeters long and about 2 millimeters wide, matt, dark brown nut fruits are formed , which have a bicovex (curved on both sides) or triangular (trigonal) shape with a grainy, matt, finely warty, rough surface. Only the fruits of the kleistogamous flowers are completely irregular in shape. All fruits are dull black or dark brown in color. The dry flower shell sticks to the fruit.

Chromosome set

The set of chromosomes of the water pepper is double with 2n = 20, less often 22 chromosomes.

Distribution and locations

The water pepper is widespread in temperate Eurasia and North America , it probably originated in Europe or Eurasia and was introduced to North America early on. In Europe, the range includes the British Isles and extends in the north to latitude 65 ° north. However, a few occurrences are also further north and even beyond the Arctic Circle. To the east the distribution area includes Japan, the People's Republic of China and Korea. The southern border of the distribution area in Southeast Asia runs through Malaysia, on the Indian subcontinent through Sri Lanka. Stocks also exist in the Philippines, New Zealand, and Queensland and South Australia. In North America, stocks are found in the United States and Canada.

On the British Isles the water pepper reaches altitudes of up to about 500 meters, in the People's Republic of China, however, the species is widespread up to altitudes of 3500 meters. Locations are never far from the water. Areas that are flooded in winter are preferred. The species can be found anywhere where it is humid enough, for example in wet clearings, in swamps, on river, lake and canal banks or simply damp places. The plants rarely stand alone and mostly in large clumps of several hundred individuals.

Water pepper is very tolerant of the substrate and colonizes both loamy and sandy soils . It has been reported from Ireland that calcareous soils are preferred. However, the soil must have a high early supply of nitrate and calcium, the cation exchange capacity should be moderate, and the pH should be around six. The species also colonizes grazed areas and is very hard-wearing.

In terms of plant sociology , the water pepper is a species of the class Bidentetea (tripartitae) (two-tooth mud bank society), according to Oberdorfer even a species of the Bidention association. But it also occurs in societies of the Bidentetalia or Polygono-Chenpodietalia orders. In the Allgäu Alps, it rises to an altitude of 1250 meters.

ingredients

Leaves and fruits contain the hot substance polygodial , which is called tadeonal . Chemically, it is a drimane- sesquiterpene - dialdehyde with a bicyclic structure. This substance acts as a feeding inhibitor for insects.

In addition, leaves and fruit contain essential oils from α-pinene , β-pinene, 1,4-cineole , fenchone , α-phellandren and α-humulene , β-caryophyllene , trans-α-bergamot . In addition, traces of carboxylic acids such as valeric acid and caproic acid and their esters were found.

ecology

The water pepper is a therophyte , is around six months old and flowers from six to ten weeks of age. Vegetative reproduction does not take place in practice, even if separated stem parts, provided they contain at least one knot, can grow out again. It is rooted up to 120 centimeters deep.

The reproduction occurs almost exclusively generatively via seeds, it is Amphimixis . Each plant produces between 300 and 400 seeds in its lifetime. These float on water, which certainly contributes to their spread, and they also stick to the feet of animals in the mud and are thus carried away.

About 3% of the seeds germinate in sand, 66% on clay, but 0% in peat. The seeds can only germinate if they have previously been in water for some time at temperatures between 2 and 4 ° C. The seed is not sensitive to light and germinates in five to ten days. The germination is delayed aboveground (epigeal). First the nut breaks open at the top and the root appears. Then the nut is lifted out of the ground and falls off as the cotyledons ( cotyledons ) expand . The cotyledons are initially red, but quickly turn green when exposed to light.

The flowers pollinate themselves. Insect visits are rare, but occasionally aphids (Aphidoidea) visit the flowers and suck on the underside of the leaf or on the flower stalk on the phloem . The species is a forage plant for the larvae of Phytobius waltoni , a species of the weevil (Curculionidae).

The flowers are occasionally attacked by Sphacelotheca hydropiperis , a very specialized type of smut fungi (Ustilaginomycetes). The less specialized rusts (Urediniomycetes) Ustilago cordae and Microbotryum cordae and the Rußtaupilz (Capnodiales) Septoria polygonorum infested the type regularly.

Mammals do not eat the water pepper, they are probably deterred by the peppery taste, the food value of the species is zero. However, the fruits are eaten by the house sparrow ( Passer domesticus ).

Systematics

First publication Polygonum hydropiper by Carl von Linné from the Species Plantarum

Botanical history and taxonomy

It was first published under the name ( Basionym ) Polygonum hydropiper by Carl von Linné in the first volume of his Species Plantarum on page 361. Linné first assigned the species to the genus of the knotweed ( Polygonum ). The first publication was based on several type copies (syntypes). The new combination to Persicaria hydropiper (L.) Delarb. was published in 1800 by Antoine Delarbre . This assignment to the genus of the knotweed ( Persicaria ) was adopted in 1841 by Édouard Spach and in 1852 by Philipp Maximilian Opiz . In 1994 a type specimen ( lectotype ) was subsequently determined. Homonyms are: Persicaria hydropiper (L.) Opiz ( Seznam Rostlin Kvĕteny České , 1852, p. 72), Persicaria hydropiper (L.) Spach ( Histoire Naturelle des Végétaux. Phanérogames , 10, 1841, p. 536). Further synonyms are: Persicaria acris Gray nom. illegal. (nom. superfl.), Polygonum acre Lam. nom. illegal. (nom. superfl.).

etymology

The water pepper on the one hand on the pepper-like taste of the leaves and fruit and, secondly, to the damp locations of the species. The scientific epithet hydropiper goes directly to the classical Greek name ὑδροπέπερι hydropeperi back with the water pepper in Vienna Dioscorides is called . The name is made up of ὕδωρ hydor for water and πέπερι peperi for pepper.

External system

So far there has been no cladistic study of the relationships between the species of the genus Persicaria . It is clear, however, that the genus is not monophyletic , but rather must be more clearly differentiated from the genus Polygonum - and possibly also from Atraphaxis , Bistorta and Koenigia .

The closest relative of Persicaria hydropiper is very likely Persicaria foliosa (H. Lindb.) Kitag. Natural hybrids are virtually excluded because of self-pollination, but hybrids with this species have been reported.

Internal system

Persicaria hydropiper is very variable. However, the reddening of the leaves can be traced back to the age of the plants and the strength of the light exposure. Specimens in full sun turn almost completely red in August. The different number of flower organs does not justify any further subdivision of the species. Nevertheless, four forms are distinguished:

Persicaria hydropiper f. hydropiper : with lanceolate leaves
Persicaria hydropiper f. obtusifolium A.Br. : with small obtuse oval-lanceolate leaves
Persicaria hydropiper f. angustifolium ( Duval ) A.Br. : with very narrow linear-lanceolate leaves
Persicaria hydropiper f. densiflorum A.Br. : with short cylindrical, very dense inflorescences

use

During excavations in the Lea Valley , very old seeds were found, but they could not be clearly assigned to the water pepper. Its use as a spice in the Bronze Age is certain, as has been confirmed by the finds of seeds in many excavations.

Today water pepper is mainly important as a field weed .

The sharp-tasting leaves were occasionally used as a pepper substitute in Europe in modern times, especially in times of need. However, since the end of the Second World War, water pepper has no longer played a role in Europe.

In Japanese cuisine , fresh water pepper leaves ヤナギタデ yanagi-tade are regularly used as a decoration for salads or rice dishes.

In addition to the natural forms, there are various varieties in Japan that were created through plant breeding . The 'Benitade' and 'Aotade' varieties are particularly successful. Some of the cultivated forms show a high genetic variance compared to the wild forms.

literature

J. Timson: Polygonum Hydropiper L. In: The Journal of Ecology . tape 54 , no. 3 , November 1966, p. 815-821 , JSTOR : 2257819 (abstract).
Alisa E. Grabovskaya-Borodina: Polygonum hydropiper Linnaeus . In: Flora of China . tape 5 , p. 291 ( efloras.org [accessed May 8, 2008]).
Harold R. Hinds, Craig C. Freeman: Persicaria. : Persicaria hydropiper - same text online as the printed work, In: Flora of North America Editorial Committee (Ed.): Flora of North America North of Mexico. Volume 5. Magnoliophyta: Caryophyllidae, part 2 , Oxford University Press, New York and Oxford, 2005, ISBN 0-19-522211-3 .

Individual evidence

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

↑ ^a ^b ^c Erich Oberdorfer : Plant-sociological excursion flora for Germany and neighboring areas. 8th edition. Verlag Eugen Ulmer, Stuttgart 2001, ISBN 3-8001-3131-5 . P. 337.

^ ^A ^b S. E. Sultan, AM Wilczek, SD Hann, BJ Brosi: Contrasting ecological breadth of co-occurring annual Polygonum species . In: Journal of Ecology . tape 86 , no. 3 , June 1998, pp. 363-383 , doi : 10.1046 / j.1365-2745.1998.00265.x .

↑ Arne Anderberg: Persicaria hydropiper (L.) Spach - Bitterpilört. In: The virtuella floran. November 8, 2005, accessed May 17, 2008 (se).

↑ Erhard Dörr, Wolfgang Lippert : Flora of the Allgäu and its surroundings. Volume 1, IHW, Eching 2001, ISBN 3-930167-50-6 , p. 452.

↑ Murray Isman: Insect antifeedants . In: Pesticide Outlook . tape 13 , 2002, p. 152-157 , doi : 10.1039 / b206507j .

↑ Gernot Katzer: Water pepper (Persicaria hydropiper (L.) Spach). In: Gernot Katzer's spice pages. November 27, 2000, accessed December 2, 2012 .

↑ Persicaria hydropiper (L.) Spach (Water-pepper) . (No longer available online.) In: BioImages: The Virtual Field Guide (UK) . August 28, 1999, archived from the original on October 7, 2008 ; Retrieved May 8, 2008 .

↑ M. Petrak: Food value number and intensity of irrigation of selected food plants of the fallow deer (Cervus dama Linné, 1758) . In: Journal for Hunting Science . tape 33 , no. 2 , June 1987, ISSN 0044-2887 , pp. 98-105 , doi : 10.1007 / BF02241759 .

^ Carl Eckstein: Contributions to the food theory of birds . In: Journal of Ornithology . tape 35 , no. July 3 , 1887, ISSN 0021-8375 , doi : 10.1007 / BF02008588 .

↑ Carl von Linné: Species Plantarum . In: Nordic Journal of Botany . tape 1 , 1753, pp. 361 ( biodiversitylibrary.org ).

↑ Persicaria hydropiper in the Germplasm Resources Information Network (GRIN), USDA , ARS , National Genetic Resources Program. National Germplasm Resources Laboratory, Beltsville, Maryland. Retrieved October 7, 2015.

↑ Persicaria hydropiper at Tropicos.org. Missouri Botanical Garden, St. Louis, accessed October 7, 2015.

^ Stefan Ekman, Tommy Knutsson: Nomenclatural notes on Persicaria . In: Nordic Journal of Botany . tape 14 , no. 1 , 1994, p. 23-25 , doi : 10.1111 / j.1756-1051.1994.tb00564.x .

↑ Helmut Genaust: Etymological dictionary of botanical plant names. 3rd, completely revised and expanded edition. Nikol, Hamburg 2005, ISBN 3-937872-16-7 (reprint from 1996).

↑ Ann S. Lamb Frye, Kathleen A. Kron: rbcL Phylogeny and Character Evolution in Polygonaceae . In: Systematic Botany . tape 28 , no. 2 , April 2003, p. 326-332 ( abstract ).

↑ ^a ^b Kentaro Yasuda, Hirofumi Yamaguchi: Genetic Diversity of Vegetable Water Pepper (Persicaria hydropiper (L.) Spach) as Revealed by RAPD Markers . In: Breeding Science . tape 55 , no. 1 , 2005, ISSN 1344-7610 , p. 7-14 , doi : 10.1270 / jsbbs.55.7 .

↑ Klaus Arlt, Thomas Eggers: Natural vegetation - field weed vegetation . In: Series of publications by the BML “Applied Science” issue 465 “Biological Diversity in Ecosystems” . 1997, p. 20–28 ( genres.de [PDF]).