Woolly thimble

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Woolly thimble
Digitalis lanata

Digitalis lanata

Systematics
Asterids
Euasterids I
Order : Mint family (Lamiales)
Family : Plantain family (Plantaginaceae)
Genre : Thimbles ( digitalis )
Type : Woolly thimble
Scientific name
Digitalis lanata
Honor

The woolly foxglove ( Digitalis lanata ), also woolly foxglove , is a species of plant from the plantain family (Plantaginaceae). Along with the red foxglove ( Digitalis purpurea ), it is the most important medicinal plant among the foxgloves ( digitalis ).

description

Habit with inflorescence
Plants in the first year only with a basal leaf rosette
Inflorescence with giant flower (pseudo-pelorie)

The woolly foxglove is a biennial to perennial herbaceous plant that reaches heights of up to 90 cm. It has elongated, lanceolate leaves on the long, blue-purple-colored stems . The stomata are anomocytic , there are no guard hairs, glandular hairs very rarely (if present, then a single-celled stalk and one- or two-celled head, epidermal cells are knotty and thickened).

The inflorescence contains many small white to creamy yellow flowers with brown veins. The bracts of the inflorescence are woolly hairy, hence the name of this plant species.

The number of chromosomes is 2n = 56.

distribution

The species occurs in cultures and gardens and is occasionally feral from it. The home is the Pontic climatic and flora area of Hungary and Southeast Europe. In Austria and North America this species is a neophyte. Only one company in Germany is still growing the woolly thimble on a large scale.

use

All parts of the woolly foxglove plant are highly poisonous. It is cultivated worldwide as a medicinal plant for the industrial production of cardiac digitalis glycosides , which chemically belong to the cardenolide glycosides . The active ingredient obtained from the dried leaves is used as a raw material for medicines for the treatment of heart failure . An optimal active ingredient content is achieved in the autumn of the first year of cultivation.

ecology

The species is found particularly in warm, sunny ruderal locations on dry, mostly chalky, sandy-stony soils. In the first vegetation period of the plant, only a basic rosette of leaves is formed, the flower stem then grows in the following year.

physiology

Especially in the first year there is a high resistance to drought stress (lack of water, water stress), the leaves remain juicy (turgescent) down to a very low water potential of the leaf, which is based on the osmotic adaptation through the formation of non- ionic substances in the leaves. The reduction in photosynthesis caused by drought stress is reversible within a few hours after irrigation. Parallel to the reduction in photosynthetic activity, the quantum yield of photosystem 2 is also reduced in the event of water stress .

ingredients

The more than 70 bitter, heart-active glycosides which are found in the leaves and which are derived from the 5 genes digitoxigenin , gitoxigenin , digoxigenin , diginatigenin and gitaloxigenin , can be regarded as effective protection against eating . Their concentration can be significantly increased in greenhouse cultivation through heat and increased carbon dioxide concentration ( carbon dioxide fertilization ).

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Individual evidence

  1. ^ Erich Oberdorfer : Plant-sociological excursion flora for Germany and neighboring areas . With the collaboration of Angelika Schwabe and Theo Müller. 8th, heavily revised and expanded edition. Eugen Ulmer, Stuttgart (Hohenheim) 2001, ISBN 3-8001-3131-5 , pp.  846 .
  2. Dimitri Hartl: Scrophulariaceae . In: Gustav Hegi : Illustrierte Flora von Mitteleuropa, 2nd edition, Volume 4, 1st part, pages 129-132. Carl Hanser Publishing House, Munich 1965
  3. Digitalis: Cultivation and synthesis difficult Pharmaceutical newspaper of October 27, 2014, accessed on September 4, 2016
  4. Hansjörg Hagels and Tatjana Wolf: Pre- and post-harvest process steps on medicinal plants 6th symposium medicinal and aromatic plants, Humboldt-Universität zu Berlin , Agricultural-Horticultural Faculty, Berlin, 19. – 22. September 2011
  5. Thomas Stuhlfauth, Dieter F. Sältemeyer, Stefanie Weinz and Heinrich P. Fock, Fluorescence quenching and gas exchange in a water stressed C3 Plant, Digitalis lanata, Plant Physiol. (1988) 86, 0246-0250 [1]
  6. HP Fock, K. Biehler and T. Stuhlfauth, Use and degradation of light energy in water-stressed Digitalis lanata, Photosynthetica 27 (4): 571-577, 1992
  7. Hildebert Wagner, Pharmaceutical Biology, 2. Drugs and their ingredients, Gustav Fischer Verlag, Stuttgart 1980
  8. T. Stuhlfauth and HP Fock, effect of whole season CO2 enrichment on the cultivation of a medicinal plant, Digitalis lanata, J. Agronomy & Crop Science 164, 168-173, 1990. doi : 10.1111 / j.1439-037X.1990 .tb00803.x

Web links

Commons : Wolliger Foxhut ( Digitalis lanata )  - album with pictures, videos and audio files