Эвенинг Праймроуз двулетняя: описание и свойства

Species of flowering plant

Oenothera biennis, the common evening primrose, is a species of flowering plant in the family Onagraceae, native to eastern and central North America, from Newfoundland west to Alberta, southeast to Florida, and southwest to Texas, and widely naturalized elsewhere in temperate and subtropical regions. Evening primrose oil is produced from the plant.

Oenothera biennis usually has a life span of two years (biennial) growing to tall in the seeding year. The leaves are lanceolate, long and wide,

Most commonly, O. biennis grows as a low, spreading herb in the first year, just a few centimetres tall, with its leaves spreading out in a rosette to cover the ground, whilst storing energy in a thick root. In the second year, it grows up much taller, to around 1.6M tall, on a semi woody stem, which then flowers and seeds. This will usually die at first frosts, but occasionally grows another stem in the third year.

Blooming lasts from late spring to late summer. The flowers are hermaphrodite, produced on a tall spike and only last until the following noon. They open visibly fast every evening producing an interesting spectacle, hence the name "evening primrose". The blooms are yellow, diameter, with four bilobed petals. The flower structure has a bright nectar guide pattern, invisible to the naked eye. This pattern is apparent under ultraviolet light and visible to its pollinators, moths, butterflies, and bees. The fruit is a capsule long and broad, containing numerous long seeds, released when the capsule splits into four sections at maturity.

This plant is a weedy species that favors disturbed environments. It has been introduced and become established on all continents except Antarctica. The seeds of the plant are important food for birds, including American goldfinch, Northern bobwhite, and mourning dove, and it is a larval host for both the primrose moth and the white lined sphinx moth. Bumblebees and honeybees also visit the flowers. The evening primrose was introduced to Europe in the early 17th century as an ornamental plant in botanical gardens where its flowers are favored for nectar by pollinators, such as bees, and its seeds are food for birds. The proteins are especially rich in the sulphur containing amino acids, methionine and cysteine, and tryptophan. Gamma linolenic acid (GLA), and linoleic acid are present. Mainly for these polyunsaturated fatty acids, evening primrose oil is sold as a dietary supplement. The Mayo Clinic stated there was no good evidence that it affected eczema, diabetic neuropathy or premenstrual syndrome. The American Cancer Society stated that there was little evidence for its effectiveness as an anti cancer agent, for which it is sometimes promoted, and "neither GLA nor other GLA rich supplements (such as evening primrose oil) have been convincingly shown to be useful in preventing or treating any other health conditions."

Evening primrose oil is considered likely as safe in recommended doses. It may increase the risk of bleeding, a concern for patients with bleeding disorders or taking drugs that may increase bleeding. The Mayo Clinic recommends caution in people with seizure disorders or mania, and by pregnant or breastfeeding women, and publishes a long list of possible side effects. Oral use of evening primrose oil may cause headaches or nausea.

The whole plant and especially the leaves are traditionally boiled to tea by Anishinaabe tribes as an energy stimulant and to facilitate weight loss. These tribes also use the roots externally as a poultice to treat piles and boils. Additionally, they may be chewed and rubbed onto the muscles to improve strength.

The knowledge of agricultural practices in the cultivation of evening primrose is relatively new and only pertain to the commercialized production of evening primrose seed oil. Information of agricultural practices for the production of root vegetable or other plant parts is not known yet. The evening primrose prefers sunny, and arid places with loamy soil and occurs below above sea level. One important prerequisite is to meet adequate nitrogen requirements. While too high nitrogen levels could lead to a quality and quantity decline of the oil content in the seeds, moderate nitrogen levels lead to increased seed quality and quantity. Because the evening primrose is a light dependent germinator, it is important that the seeds are not planted too deep into the soil, about deep. The cultivation of evening primrose is thus suitable for no till farming, but the plants require an intense mechanical weed control. The seeds are tiny, about They need approximately two to three weeks to germinate and are therefore very susceptible to the outgrowth of weeds. Evening primrose seeds can be sown in the first half of April (spring seeds) or from mid July to mid August (autumn seeds). The time of harvest is approximately 75 to 80 days (spring seeds) or 100 days (autumn seeds) after flowering, and clearly influenced by the plant variety, climate conditions, soil fertility and sowing time. The population development and thus seed maturation of the evening primrose is very heterogeneous which is a rather difficult production factor. There is not much water needed during the vegetation period. A study has shown, that the irrigation with salt water could increase the oil yield and quality in evening primrose seeds. This might be a great opportunity especially in regions with limited water resources. Thus, the evening primrose could be a valuable alternative oil crop in arid regions. Finally, the cultivation of evening primrose requires a proper field management otherwise the plant can become invasive. If the seeds are used for pharmaceutical purposes it is also important to grow the evening primrose without any pesticides to avoid any chemical residues.