Phacelia
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Tansy phacelia ( Phacelia tanacetifolia ) |
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| Scientific name | ||||||||||||
| Phacelia | ||||||||||||
| Yuss. |
The genus Phacelia belongs to the subfamily of the water leaf family (Hydrophylloideae) in the family of the predatory leaf family (Boraginaceae). The common names Bienenweide , Bienenfreund , Büschelschön or Büschelblume are also used.
description
Vegetative characteristics
Phacelia species grow as annual , biennial or perennial herbaceous plants . The aboveground plant parts are mostly hairy. The alternate and spirally arranged leaves are simple or compound. Stipules are missing.
Generative characteristics
The terminal, zymous inflorescences are unilaterally and often rolled up like a snail.
The hermaphroditic flowers are radial symmetry and five-fold with a double flower envelope . The five blue-violet, light blue to white petals are bell-shaped to wheel-shaped together. There is only one circle with five free, fertile stamens . Most of the anthers are hairy. Two carpels have become a top permanent ovary grown. There is only one stylus.
The capsule fruits are double-faced and hairy.
ecology
Pollination is accomplished by Hymenoptera (Hymenoptera) ( Entomophilie ).
Occurrence
The original home of the genus Phacelia is mainly western North America, the eastern USA and South America, i.e. only the New World . Few species of Phacelia occur wild on roadsides and roadsides, in fields and rubble sites. The species of the genus are undemanding and tolerate drought, but not winter hardy. That is why they cannot establish themselves as neophytes on a large scale in Central Europe .
Use fewer species and varieties
Most cultivated in agriculture are varieties of the tansy phacelia ( Phacelia tanacetifolia ).
Use as a beekeeper plant
Phacelia is often sown as a bee pasture in Central Europe . It is considered a very high-yielding bee forage plant, the value of which is roughly equivalent to that of rapeseed or buckwheat . Each flower produces nectar with a total sugar content of between 0.7 and one milligram in 24 hours. Yields of 500 kg honey per hectare and flowering season are quite possible.
Use as a soil improver
Phacelia is very suitable as a green manure plant . With its dense root system, it makes good use of the nutrient reserves in the soil and, after rotting, easily passes them on to the next crop. It leaves a tightly rooted, cooked crumb. The delicate leaves lead to very good soil shading and effective weed suppression. The high amounts of organic material that remain in the soil maintain or increase the humus content and thus the productivity of the soil. This improves the soil structure and the yield security increases in the long term, even on lighter soils.
Since the stands generally freeze and collapse in winter at temperatures below minus 5 ° C, subsequent crops at risk of erosion, such as sugar beet , can be sown as mulch or direct sowing without plowing into the plant remains .
Resistance to pests, inhibition of pests
The phacelia is like as a cover crop grown and green manure, because it is the only crop in the subfamily of Hydrophylloideae. This means that there are no problems with crop rotation , as is often the case with related clans. In contrast, in the case of cruciferous crops such as rape , cabbage and radish, the occurrence of family-specific diseases such as clubhead is favored if the crop rotation is not adhered to. In crop rotations with sugar beet , the cultivation of phacelia is advantageous because it has an inhibiting effect on nematodes ( beet roots ).
Use in viticulture
For intermediate greening in viticulture, around 10 to 12 kg of seeds are sown per hectare in spring. Since it has a very high mass output and is a so-called nitrogen collector, it is preferred for first green roofs.
Use as animal feed
Phacelia harvested before the start of flowering can also be used as easily digestible feed , for example when feeding sows . In addition to being fed fresh, it can also be preserved by ensiling .
Importance in genetics
Using the example of also in North America occurring Phacelia magellanica group could be shown that reproductive barriers between species in the plant kingdom work far less well than in the animal kingdom, or in other words, that plant genomes can be flexible much.
The Phacelia magellanica group includes species with several levels of ploidy , that is, there are races that are diploid , tetraploid and hexaploid and that do not interbreed or only poorly. The tetraploids of the different species, on the other hand, cross each other relatively easily. The exchange of genes between the “tetraploids of different species” is therefore easier than between the ploidy races of the same species.
Systematics
The genus Phacelia was established by Antoine Laurent de Jussieu . The generic name Phacelia is derived from the Greek word phakelos for "tuft".
There are 150 to 200 Phacelia species (selection):
- Phacelia argentea A. Nelson & JFMacbr. : It occurs only in Oregon and California.
- Phacelia calthifolia Brand
- Bell phacelia or desert blue bell ( Phacelia campanularia A.Gray ): It occurs only in California.
- Phacelia Fremontii Torr. : It occurs in California, Arizona, southern Nevada and southwestern Utah.
- Large-flowered phacelia ( Phacelia grandiflora A. Gray )
- Phacelia magellanica (Lam.) Coville
- Small phacelia ( Phacelia minor (Harv.) Thell. Ex Zimm. ): It occurs only in California and Mexico
- Parry phacelia ( Phacelia parryi Torr. ): It occurs only in California and Mexico.
- Phacelia rotundifolia Torr. ex S. Watson
- Phacelia secunda J.F. Gmel.
- Silky-haired phacelia ( Phacelia sericea (Graham) A.Gray ): It is only found in Canada and the USA
- Tansy phacelia ( Phacelia tanacetifolia Benth. ): It is native to California, Nevada, Arizona and Mexico, but the species is also introduced in Europe, Australia and New Zealand.
- Sticky Phacelia ( Phacelia viscida (Benth.) Torr. ): It is native to California and Mexico.
Individual evidence
- ↑ Seed reproductive areas Phacelia tanacetifolia - Plant genetic resources in Germany.
- ↑ Josef Lipp et al .: Handbook of Apiculture - The Honey . 3., rework. Ed., Ulmer, Stuttgart 1994, ISBN 3-8001-7417-0 , p. 37 ff.
- ↑ Klaus-Ulrich Heyland (Ed.): Special plant cultivation. 7th edition. Ulmer, Stuttgart 1952/1996, ISBN 3-8001-1080-6 , p. 94.
- ↑ Guide to part-time greening in viticulture - State teaching and research institute for viticulture and fruit growing, Weinsberg.
- ^ Klaus-Ulrich Heyland (editor): Special plant cultivation. 7th edition, Ulmer, Stuttgart 1952/1996, ISBN 3-8001-1080-6 , pp. 94, 302
- ↑ a b c d e f g h Boraginaceae in the Germplasm Resources Information Network (GRIN), USDA , ARS , National Genetic Resources Program. National Germplasm Resources Laboratory, Beltsville, Maryland. Retrieved February 22, 2014.
