Onion（Allium cepa50. ) is Lycoriaceae AlliumBiennial herbBotany。The root of onion is string fibrous root;The stem is shortened into a stem disc, which is flat and conical;The leaf is composed of leaf body and leaf sheath. The leaf body is dark green and cylindrical;The base of the leaf sheath expands to form a bulb at the initial stage of growth, and each plant will form a bulb similar to a ball, with purple red, pink, copper yellow, light yellow or white colors;The flowering and fruiting periods are from May to July.As early as the third century AD, when the Silk Road was opened in the Western Han Dynasty, it was gradually introduced into China. Because it was a foreign object, it was called "onion", or onion.[11-15][22]
Onions have been cultivated since ancient Egypt, and later spread to various places by Spanish colonists, but they are mainly planted in temperate regions such as Italy, Mexico, Spain and the United States.Onions are resistant to drought, moisture and fertilizer, but not resistant to high temperature, strong light, drought and barren, with good quality and high yield. They are widely cultivated by seed reproduction. Because they are easy to store and can be cultivated continuously, they are suitable for family garden planting.[16-19]
According to Qingyi Record, onions can reduce cholesterol, soften blood vessels, benefit stomach and intestines, resist cold and kill bacteria.In foreign countries, it is known as the queen of dishes, with high nutritional value.Onions can be used as food condiments, while pearl onions are usually used as accessories or condiments in cocktails.At the same time, the unique pungent flavor of onion is propylene disulfide, which can promote metabolism.Eating onions can also make people energetic and eliminate fatigue.[11][15][20-21]It can also cause gastrointestinal discomfort.[24]
Onions are native toCentral AsiaOr West Asia, there are many different varieties, which have been used for food around the world.In 1000 BC, there were pictures of harvesting onions in ancient Egyptian stone carvings, which later spread to the Mediterranean region.In the Western Han Dynasty,diplomat famed for exploits in Inner AsiaIt leads to the Western Regions and brings back many species from the Western Regions.At that time, there were records of onion planting in the Western Regions.After the great geographical discovery, it spread from Europe to the world.In the 16th century, it was introduced into North America.It spread to Japan in the 17th century.In the 18th century, "Lingnan Miscellaneous Records" recorded that onions were introduced into Macao from white Europeans and planted in Guangdong.
According to the data of Che Chengcheng Office, in 1912, a Japanese primary school teacher who taught in Tamsui introduced onions to Taiwan for the first time from Japan.Since 1918, the Taiwan Governor's Office Agricultural Experiment Institute has experimented with planting onions all over Taiwan, but the results are poor.
After the end of the Second World War, the Taiwan Provincial Agricultural Experiment Institute, under the sponsorship of the Provincial Department of Agriculture and Forestry and the Agricultural Resumption Conference, continued to introduce various varieties of onions and trial planted them throughout Taiwan.In Yunlin, southern TaiwanChiayi, Tainan and Pingdong have been planted successfully. Hengchun, Fenggang, Checheng and other places have become the largest onion producing areas in Taiwan.
As early as the third century AD, when the Silk Road was opened in the Western Han Dynasty, it was gradually introduced into China. Because it was a foreign object, it was called "onion", or onion.[11-15]
Onions are biennial orPerennial herb。The root is string shaped, and the thick green cylinder shaped hollow leaves are waxy on the surface;The leaf sheath is thick and scaly, which is concentrated around the shortened stem, formingbulb(commonly known as onion);Umbrella, white floret;Capsule.The outer side of the rhizome is covered with a thin layer of skin (white, yellow or red), and the inner side is covered with layers of meat, usually white or light yellow.[23]
The radicle of onion will shrink soon after being buried in the soil, so there is no main root. Its root is stringy fibrous root, which is born at the base of the shortened stem disc. The root system is weak, without root hair. The root system is mainly distributed in the 20 cm surface soil layerDrought toleranceWeak sex, weak ability to absorb fertilizer and water.The root growth temperature is lower than that above the ground. When the ground temperature is 5 ℃, the root starts to grow. The optimum temperature is 10~15 ℃, and the growth is slow when the ground temperature is 24~25 ℃.
onion
During the vegetative growth period of onion stem, the stem shrinks to form a flat conical stem disc. The lower part of the stem disc is the heel of the disc. The upper part of the stem disc is surrounded by circular cylindrical leaf sheaths and buds, and fibrous roots grow below.maturebulbThe dry shrinkage and hardening of the heel tissue can prevent water from entering the bulb.Therefore, the heel can control the early growth of the root or the early germination of the bulb. During the reproductive growth period, the plant undergoes low temperature and long sunshine, and the growth cone begins to flower bud differentiation and sproutFlowering boltThe flower stalk is tubular, hollow, and swollen in the middle. There is wax powder, and the top forms an inflorescence, which can blossom and bear fruit.Onion head ball due toflorescenceDegenerate, forming aerial bulb in flower bud.
Onion leaves are composed of leaf body and leaf sheath. The leaf sheath forms pseudostem and bulb. The leaf body is dark green, cylindrical, hollow, and has concave grooves on the abdomen (one of the morphological signs that distinguish onion from young seedlings).The tubular leaves of onion grow vertically, with small leaf area and thick wax powder on the leaf surface, which is an ecological feature of drought resistance.
Scape stout, up to 1 m high, hollow cylindrical, expanded below the middle, gradually narrowed upward, and the lower part was covered with leaf sheaths;Involucre 2-3 lobed;Umbrella globose, with many and dense flowers;Pedicel about 2.5 cm long.Pollen white;Perianth segments with green midvein, oblong ovate, 4-5 mm long, about 2 mm wide;Filaments are equal in length, slightly longer than the perianth segments, connate at about 1/5 of the base, and the lower 1/2 of the connate part is adnate to the perianth segments. The base of the inner ring filament is extremely enlarged, and each side of the enlarged part has 1 tooth, and the outer ring is conical;ovary: Near spherical, concave honeyhole with curtain at the base of abdominal suture;The style is about 4 mm long.The flowering and fruiting period is from May to July.[1]
Growth environment
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temperature
onion
Onions have strong adaptability to temperature.Seeds andbulbIt can germinate slowly at 3~5 ℃, and accelerate at 12 ℃. The suitable temperature for growth is 12~20 ℃ for seedlings, 18~20 ℃ for leaves, 20~26 ℃ for bulbs, and 6~7 ℃ for healthy seedlings.Bulb expansion needs higher temperature. Bulb cannot expand below 15 ℃, and the best growth is at 21~27 ℃.If the temperature is too high, the growth will decline and go into dormancy.[2]
illumination
Onion is a long sunshine crop, which needs more than 14 hours of long sunshine at bulb expansion stage and bolting and flowering stage.Under the condition of high temperature and short sunshine, only leaves grow and onion cannot be formed.The suitable light intensity of onion is 20000~40000Lux。[2]
water content
Onions should be supplied with sufficient water during germination, seedling growth and bulb expansion.However, water should be controlled at seedling stage and before overwintering to prevent seedlings from growing excessively and suffering from freezing damage.Irrigation shall be controlled 12 weeks before harvest to enrich the bulb tissue, accelerate the maturity and prevent the cracking of the bulb.Onion leaf body is drought resistant and suitable for 60%~70% humidity. Excessive air humidity is prone to disease.[2]
Soil and nutrition
Onions have strong adaptability to soil. It is better to use fertile, loose and well aerated neutral loam. Sandy loam is easy to obtain high yield, but clay loam has full bulbs, good color and good storage resistance.The ability of onion roots to absorb fertilizer is weak, and sufficient nutrition conditions are needed for high yield.Every 1000 kg of onion needs to absorb 2 kg of nitrogen, 0.8 kg of phosphorus and 2.2 kg of potassium from the soil.The application of trace elements such as copper, boron and sulfur has a significant effect on yield increase.
MoreSeed reproductionIt is widely cultivated and suitable for family garden planting because of its easy storage and continuous cropping.[16-19]
Seed collection method
Bulblet seed collection method:This is the seed collection method adopted in most areas of China, and the mother plant uses mature big bulbs.Sowing from September to October of the first year, and seedlings are exposed or stored for overwintering in winter.Big bulbs will be harvested in the summer of the second year, and good individuals will be selected from them. The susceptible plants will be eliminated after four years of storage. They will be planted in the field from September to November. In the spring of the third year in severe cold areas, they will be planted with female bulbs, and seeds will be harvested in June. It will take about 21 to 23 months from sowing to harvesting seeds.This seed collection method has been selected for many times in the field and during the storage period, and its variety purity and seed nature are significantly higher than those of the two-year seed collection method, which can be used as the original seed production.The disadvantage is that the seed collection cycle is long, the storage is laborious, the use of large bulbs is more, and the cost is high.
Bulblet seed collection method: The method often used in spring sowing areas.In early spring, the soil thaws and the seedlings are sown directly at an early time. In summer, the bulbs with a diameter of more than 3 cm are mature. After storage and overwintering, the bulbs are planted for seed collection in the next year. From sowing to harvest, about 16 to 19 months, which shortens the seed collection cycle and reduces the cost, and can be used for seed reproduction and production. However, the characteristics of immature bulbs are degraded due to the selection of their properties.
Small plant seed collection methodIt is also called non heading seed collection method. It is sown from July to September in the first year, and grows into large seedlings before winter. It meets the green body vernalization standard and passes the vernalization stage to ensure that plants will bolt and blossom in the second year. The period before and after is about 11 to 13 months, which shortens the seed collection period, but does not formbulbAt the same time, because of the inheritance of early bolting traits, this will lead to the failure of bulb cultivation in production.
Continuous seed collection: After the seeds are collected by using the big bulb seed method, several small bulbs are formed at the base of the seed plant. After harvest and storage, they are planted in autumn. In dry areas, they can also spend the summer in situ. After germination, they change from one female bulb to three to four female bulbs.The number of sprouted flower stalks in the next year is the first year for seed collection, and the second year for seed collection, which reduces the cost, shortens the seed collection cycle, ensures the seed quality, and also improves the yield.
The different sphericity of onion is related to its early and late maturity. Generally, the flatter the sphericity, the earlier the maturity.Different onion varieties have different yields. Flat varieties with early maturity generally yield 4500-5500 kg per mu;Medium and late maturing varieties generally yield 5000~5500kg per mu.The economic benefit of planting onions is between 3000 and 6000 yuan per mu.It is also easy to manage and is a good model for agricultural adjustment of planting structure.It is suitable for harvesting radish and cabbage.
Seeding
Sowing date and amount
Onion sowing
Appropriate sowing time is the key to cultivate strong seedlings. Early sowing, large seedlings, easy moss pulling after overwintering, weak late sowing seedlings, poor cold resistance, small phosphorus stems, and low yield.Taking the Huanghuai River Basin as an example, the best sowing time is in the first and middle of September.It is better to conduct germination test before sowing.Under normal conditions, the seeding amount per mu of seedling bed is 4-5kg;Considering that 20% weak seedlings and inferior seedlings should be eliminated and interspersed, their cultivation area should be 15 times of the seeding bed. If the germination rate is lower than 70%, the seeding amount should be increased as appropriate.[3]
Cropping and fertilization
The border height is 1.4~1.5m,Border width27cm, 15kg of superphosphate and calcium per mu after border leveling, and 4m3 of decomposed organic soil miscellaneous fertilizer per mu as base fertilizer. After seedling emergence, quick acting nitrogen fertilizer is applied in combination with watering, and 10kg of urea is applied per mu.[3]
Underground pest control
There are 5kg phorate per mu, which shall be evenly ploughed into the soil in combination with land preparation and leveled by columbines.[3]
sow
After the border surface is leveled, water it first, and then spread it evenly.Cover 0.8cm nutrient soil to ensure that all seedlings are planted at one time.If the moisture content cannot meet the seedling emergence requirements after sowing, watering can be used to spray water to promote seedling emergence, or sowing after germination.Soak the seeds in cold water for no more than 12 hours, wrap them with wet cloth and place them in a cool place at 20~24 ℃ for germination. Wash them with clean water every day. When the seeds are just "exposed", sow them in time without delay. If the seeds are not sowed in time, the growth of radicle will cause inconvenience to the sowing work.[3]
Emergence
After emergence, attention should be paid to the prevention and control of mildew and damping off.The method is 50% carbendazim or 40% carbendazim per muChlorothalonil150g, spray 30-40kg water evenly.[3]
cultivation techniques
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Land preparation and fertilization
Ten days before sowing, plowing shall be carried out first, and the fully decomposed, mashed and screened farmyard manure shall be applied universally. The amount of fertilizer applied per mu shall not exceed 2000 kg. Then, plowing shall be carried out twice, with a depth of more than 20 cm, so that the fertilizer and soil can be fully mixed, and the border surface shall be leveled with a flat rake for sowing.There are two kinds of border specifications: one is small high border, 1.6 meters wide, 0.2 meters wide, 0.1 meters deep, and 8 rows are transplanted per border. This border is suitable for clay soil or fields with small gaps.The second is to level the border: the border is 2m wide, the border ridge is 0.27m wide, 0.2m high, and 10 rows are planted in each border.Flat border is suitable for sandy soil.[3]
Transplant density
The transplanting period can be divided into: (1) The suitable transplanting period for film covered fields is November 15-20 (around the beginning of winter);(2) The suitable transplanting period for non film covered fields is October 20 (before and after frost).The regular density shall be increased or decreased according to the soil fertility, fertilization level and management level. Generally, the row spacing is 20 cm, the plant spacing is 16~17 cm, and the density per mu is 20000 plants.In order to prevent moss pulling, it is generally advisable to select seedlings of moderate size with leaf sheath diameter of 6-7 mm and fresh weight of 4-6 grams per plant.Eliminate large, weak and inferior seedlings.Before planting, the big and small seedlings shall be planted separately and managed at different levels to increase production in a balanced way.[3]
Field management
watering
Onions enter the slow seedling stage about 20 days after planting. Due to the low air temperature during planting, they cannot be watered in large quantities. Excessive watering will reduce the ground temperature and slow down the young seedlings.At the same time, the new roots of newly planted seedlings have not yet germinated, and can not lack water.Therefore, the onion should be watered more frequently at this stage.The amount of water to be watered each time should be small. The general principle is not to wither seedlings and dry the ground, so as to promote the rapid rooting and survival of seedlings.
The onion seedlings planted in autumn will enter the wintering period after they survive. To ensure the safety of the onion seedlings planted in winter, it is necessary to timely water them for wintering.After overwintering, it turns green and enters the growth period of stems and leaves. At this stage, water is required not only to promote growth, but also to control watering to prevent overgrowth.The method of controlling watering is called "crouching". Crouching depends on weather conditions, soil properties and post planting growth conditions. Under general conditions,Crouching seedlingAbout 15 days.When the outer leaves of onion seedlings are dark green and waxy,mesophyllWhen it becomes thicker and the color of the heart leaves becomes darker, it is the end of seedling squatting and start watering.In the future, water shall be poured every 8-9 days to make the soil dry and wet, so as to promote plant growth and prevent plant overgrowth.Stop watering 7~8 days before harvesting
apply fertilizer
The requirement of onion for fertilizer is 13-15 kg of nitrogen, 8-10 kg of phosphorus and 10-12 kg of potassium per mu.Attention shall be paid to the application of phosphorus and potassium fertilizers, and excessive nitrogen fertilizer shall be avoided to avoid bolting or delaying bulb expansion due to overgrowth of aboveground. Before and after the spring onion seedlings are unearthed, the soil shall be kept moist, watered frequently, and cultivated frequently. During the peak leaf growth period and bulb expansion period, the onion needs the most fertilizer and water, so fertilization and watering shall be carried out timely,667 square meters were applied with 15 kg of diammonium phosphate, 20 kg of diammonium phosphate and 3-5 kg of potassium sulfate respectively.
After the onion is planted and before the seedling is slowed down, generally no fertilizer is applied. After overwintering, water for overwintering is combined, and 1000~1300 kg of feces and urine are applied per mu. When the onion turns green in spring, water for turning green is combined, and another turn green fertilizer is applied.
Scarification
The loose soil is beneficial to the development of onion root system and the expansion of onion bulb. Generally, it should be carried out 3~4 times at the seedling stage, combined with each watering;During the stem and leaf growth period, it shall be carried out 2-3 times, and the intertillage shall be stopped after the plant is closed.The depth of intertillage should be about 3cm. The planting plant should be shallow and the place far away from the plant should be deep.
Bolting
For early bolting onions, cut them from the lower part of the flower bud orFlowering boltThe tip is separated, and two pieces are torn from top to bottom to prevent flowering from consuming nutrients and promoteLateral budGrow to form a fuller bulb, and spray at the same timeDiguozhengdiling。It has been proved by practice that certain yield can still be obtained for early bolting plants after taking bolting removal measures.
Harvesting and storage
Onion harvesting
Picking time: onion is generally picked from the end of May to the first ten days of June.When onion leaves gradually turn yellow from bottom to top, pseudostems become soft and begin to inverted;The bulb stops expanding and its outer skin is leathery. It enters the dormancy stage, which indicates that the bulb has matured and should be harvested in time.Onions should be dried in the field for 2-3 days after harvest.The roots of the directly marketed ones can be cut off and cut off at the false stems on the upper part of the bulbs, and then they can be sold in baskets.If onions need to be stored, do not remove the stems and leaves. When the leaves are dried to 70% or 80%, braid the stems and leaves and hang them in a ventilated, cool and dry place, which is called hanging onions.
Harvesting and drying: onion for storage should be yellow skinned, oblate, large, spicy, with low moisture content and small bulb neck.The best harvest time is when the lowest 1~2 leaves of onion plant are dry and the aboveground part begins to fall.Air drying shall be carried out in time after harvesting.Method: Arrange onion plants diagonally, so that the stems and leaves of the next row just cover the onions of the previous row, so as to avoid direct exposure of onions to the sun.During drying, turn it every 2-3 days until the leaves turn yellow.
Storage method:
Onion storage
Hanging storage method.Braid the dried onion leaves into long braids, and combine the braids into bundles. Each bundle is about 60 onions, and then dry them for 5 to 6 days (to prevent rain). After the onions are fully dried and the neck is completely turned into leather, hang them under the eaves or indoors.In case of indoor hanging storage, the hanging storage room shall be well ventilated and kept dry.
Stacking method.Choose a place with high terrain and good drainage. Use straw or wheat straw as the base, and then put two layers of reed mats. Then stack the leafless onion heads on the reed mats, which are also surrounded by reed mats, and tied with ropes to avoid direct sunlight or rain infiltration.The third is the method of storage.If there is a thermostat, the onion leaves can be removed and directly spread on the shelf for storage.
Precautions: No matter which method is used for storage, care should be taken to prevent onion from rotting and sprouting.Onions are easy to rot in the early stage of storage, so they must be kept dry;In the later stage of storage, it is easy to germinate. You can spray onion plants with 0.25% fresh vegetable solution 2-3 weeks before harvest, or dip the roots with 0.25% fresh vegetable solution after harvest.
onionrust: Spray 1000 times of 20% triadimefon emulsifiable concentrates once every 7 to 10 days for 2 to 3 consecutive times.
Onion downy mildew: use 75% chlorothalonil wettable powder 600 times liquid;64% disinfectant alum wettable powder is sprayed with 500 times liquid, once every 7 to 10 days, and 2 to 3 times continuously.
White rot
onionWhite rot: Spray 500 times of 50% carbendazim wettable powder once every 7 days for 2-3 consecutive times.
Onion blight: spray 68% Jinredomel 1000 times solution once every 7 to 10 days for 2 to 3 consecutive times.
onionGray mold: Spray 1500 times of 50% paraquat wettable powder once every 10 days for 2-3 consecutive times.
onionBlack spot: Spray 600 times of 75% chlorothalonil wettable powder once every 10 days for 2-3 consecutive times.
Soft rot
Onion soft rot: Use 4000~5000 times of new phytomycin to prevent and cure, once every 7 days, and once or twice continuously.[5]
Insect pest
Onion pests mainly include root maggot, leaf miner and onion thrips.
Root maggot: 48% Lessbane emulsifiable concentrate 1000~1500 times liquid can be sprayed once every 7~10 days in the early stage of disease, and 2~3 times continuously;
Liriomyza sativae: spray 2.5% deltamethrin or 20% fenvalerate or other pyrethroid pesticides 1500~2000 times continuously for 2~3 times from the peak spawning stage to the early hatching stage of larvae;
Control of onion thrips: spray 3000 times of 5% Regent suspension or 2500 times of 10% imidacloprid wettable powder at the peak of nymph occurrence, once every 7 to 10 days, for 2 to 3 consecutive times.[6]
Species classification
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ordinary
（Allium cepa50. ) Each plant usually forms only one bulb.Seed reproduction, a few varietiesSpecial environmentBelow the inflorescence to form aerial bulbs.Common onion can be divided into oblate, round, oval and spindle shapes according to the shape of its bulb.It can also be divided into early maturity, medium maturity and late maturity.In the south of the Yangtze River, most of them are middle and early maturing species.You can also press differentGeographic latitudeThere are three types:
"Short day" type: suitable for the south of the Yangtze River in China, with latitude between 32 ° and 35 ° north latitude. Most of these varieties are sown in autumn and harvested in spring and summer.
"Long day" type: It is suitable for all parts of Northeast China, and the latitude is 35 °~40 ° north latitudeearly springSowing or planting (using bulbs), harvesting in autumn.
Middle type: suitable for the Yangtze River and Yellow River basins, between 32 ° and 40 ° north latitude.Such varieties are sown in autumn and harvested in late spring and early summer of the next year.
tillering
（Allium cepa50. Var.aggregatum G. Don) can tiller, and each plant tillers into multiple to more than 10 bulbs with irregular size, usually without seeds.Each tiller base can form a bulbBulbletreproduction.This variety has poor quality and low yield, but it is resistant to storage,Cold resistanceStrong.[7]
Terminal growth
Red onion
（Allium cepa50. Var. viviparum Metz.) has many aerial bulbs on the inflorescence.Aerial bulbs can be used for reproduction and do not bear seeds.It is mainly used for pickling.Like tillering onion, terminal onion has low economic value and is rarely cultivated except for special purposes.[7]
Red skin
The onion is purplish red in appearance, and its scales are slightly reddish, oblate or round in shape, with a diameter of 8-10 cm.It is resistant to storage and transportation, has a short dormancy period, and sprouts early, showing early to medium maturity. It is harvested from late May to early June.It is widely cultivated in East China.Representative varieties include Shanghai Hongpi, etc.[7]
Wampee
The onion is copper to light yellow, with fleshy scales, yellowish and soft, fine tissue, and strong spicy taste.It is oblate and 6-8 cm in diameter.It is relatively resistant to storage and transportation, and has early to medium maturity.The yield is lower than that of red peel seed, but the quality is better, which can be used for dehydration processing.Round or high round, suitable for export. The representative varieties are Lianyungang 84-1, DK Yellow, OP Yellow, Dabao, Laixuan 13, etc.[7]
White
The onion is white, with fleshy scales, white, oblate and spherical, and some are high round and spindle shaped, with a diameter of 5-6 cm.Good quality, suitable for dehydration processing raw materials or canned food ingredients.But the yield is low and the disease resistance is weak.Early autumn sowing in the Yangtze River basin is easy to advancebolting。Representative varieties includeHamiWhite paper, etc.
Key values
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Qingyi Record records that onions have fallencholesterolIt can soften blood vessels, benefit stomach and intestines, resist cold and kill bacteria.In foreign countries, it is known as the queen of dishes, with high nutritional value.Onions can be used as food condiments, while pearl onions are usually used as accessories or condiments in cocktails.At the same time, the unique pungent flavor of onion is propylene disulfide, which can promote metabolism.Eating onions can also make people energetic and eliminate fatigue.[11][15][20-21]
Onion is a very common cheap home dish.Its meat is tender, juicy and light in taste, good in quality, and suitable for raw food.Originated in western Asia, it is cultivated in all parts of China and can be supplied in all seasons.The edible part of onion is the underground fat bulb (i.e. onion).In foreign countries, it is known as the "Queen of Cuisine" with high nutritional value.[8]
Medicinal value
Onions are rich in nutrients, not only potassiumvitamin CFolic acid, zinc, selenium, fiber and other nutrients, as well as two special nutrients - quercetin and prostaglandin A.These two special nutrients make onions have many health benefits that cannot be replaced by other foods:
Cancer prevention
Onion's anti-cancer effect comes from its rich selenium and quercetin.Selenium is an antioxidant that can stimulate human immune response, thus inhibiting the division and growth of cancer cells, and also reducing the toxicity of carcinogens.Quercetin can inhibit the activity of cancer cells and prevent the growth of cancer cells.A survey shows that people who often eat onions are 25% less likely to suffer from stomach cancer than those who do not eat onions, and 30% less likely to die from stomach cancer.
Maintain cardiovascular health
Onion is the only vegetable known to contain prostaglandin A.Prostaglandin A can dilate blood vessels and reduce blood viscosity, thus reducing blood pressure, increasing coronary blood flow and preventing thrombosis.Rich in onionquercetin The bioavailability of quercetin is very high. According to the research report of scientists, quercetin may help prevent low-density lipoprotein（LDL）The oxidation of can provide important protection for atherosclerosis.
Stimulate appetite and help digestion
Onions contain allicin, which has a strong aroma. It often makes people cry because of its pungent smell during processing.It is this special smell that can stimulate gastric acid secretion and increase appetite.Animal experiments have also proved that onions can increase gastrointestinal tension, promote gastrointestinal peristalsis, thus playing an appetizing role, and have obvious effects on anorexia caused by atrophic gastritis, insufficient gastric motility, indigestion, etc.
Sterilization, anti cold
Onions contain plant bactericides such as allicin, which has a strong bactericidal ability and can effectively resist influenza virus and prevent colds.When discharged through the respiratory tract, urinary tract and sweat glands, this phytofungicide can stimulate the secretion of cell pipeline walls at these locations, so it also has the functions of expectoration, diuresis, sweating, bacteriostasis and antisepsis.
Tips: purple onion has higher nutritional content
According to skin color, onions can be divided into white, yellow and purple skins.From the perspective of nutritional value, purple onion has better nutrition.This is because purple skin onions are more spicy than the other two varieties, which means they contain more allicin.In addition, the purple part of purple onion contains more quercetin.
Onions have a good prevention of "wealth disease"
It is used for headache, nasal congestion, body weight, aversion to cold, fever and no sweat caused by exogenous cold.500ml Coca Cola, add 100g onion shreds, 50g ginger shreds, a small amount of brown sugar, boil it slowly for about 5 minutes, and drink it while hot.
In recent years, it has been found that onions can effectively prevent "wealth disease". Onions contain xanthuric butyric acid, which can make cells better use of sugar, thus reducing blood sugar.Onions also contain prostaglandins, which can dilate blood vessels, reduce peripheral vascular resistance, promote sodium excretion, and reduce elevated blood pressure.
Onions contain a small amount of raffinose, a functional oligosaccharide, which is an important carbohydrate for onions to resist harsh environments (cold and drought resistance).Raffinose can proliferate human bodyBifidobacteriumIt can moisten intestines, relieve constipation, reduce blood fat and blood pressure.
Onions also contain diallyl sulfide, which can prevent vascular sclerosis and reduce blood lipids.Quercus cortex like substances can also be detected in onions. The glycoside formed under the induction of flavanone has the effect of diuresis and detumescence, which is beneficial to the prevention of obesity, hyperlipidemia, arteriosclerosis and other diseases, and is consistent with the function of onion in drying dampness and detoxification.
Other effects
Prostaglandin A contained in it is a strong vasodilator, which can fight against catecholamine and other pressor substances, and promotesodium saltExcretion has the function of lowering blood pressure;
The sulfide can promote fat metabolism, reduce blood fat and prevent arteriosclerosis;
Flavonoids contained in onions can reduce the viscosity of platelets. Eating onions regularly can prevent thrombosis and reduce the probability of myocardial infarction and cerebral thrombosis;
Onions contain organic substances similar to the antidiabetic drug metsulfobutylurea, which can significantly reduce the blood sugar content;
It contains sulfide, trace element selenium, etc., which can inhibit gastric cancer, esophageal cancer, colon cancer, breast cancer, etc;
The volatile oil contained in onions can help sex. Eating onions regularly can improve the quality of sexual life for the elderly;
Onion can improve thebone densityEating onions often can prevent osteoporosis;
Onions are richvitamin C, nicotinic acid, which can promote the formation of intercellular substance and repair of damaged cells, so that the skin is smooth, ruddy, elastic and has cosmetic effect.The sulfur content and vitamin E can prevent unsaturated fatty acids from producing lipofuscin pigment, which can prevent senile plaque.[10]
Not suitable for people
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1. Onions should not be eaten by patients with skin diseases.
2. People with eye diseases cannot eat onions, which will worsen their condition.
3. Patients with gastrointestinal diseases cannot eat onions, which may lead to aggravation.
Plant culture
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Symbolize victory
During the battle between the two armies in medieval Europe, teams of cavalry were high on their horses, wearing armour, holding swords and halberds, and wearing a "necklace" around their necks. The chest pendant of this special "necklace" was a round onion head.They believe that onion is a talisman with magical power. Wearing it on the chest can avoid being stabbed by the halberd and shot by the bow and arrow, and the whole team can maintain strong combat effectiveness and win the victory.
Therefore, onion is the so-called "victory onion".In Greek, the word "onion" is derived from "armor".The ancient Greek and Roman armies believed that onions could stimulate the courage and strength of soldiers, so they added a large number of onions to their meals.
Food culture
Onions buried at the same time as the dead were found in Egyptian tombs five or six thousand years ago. Onions are also painted on the walls of the oldest building in Egypt on the sarcophagus.
Onions are one of the favorite vegetables of the Russian people, and they are also inseparable from three meals a day.Due to the short summer and long winter in Russia and the lack of sunshine, fresh seasonal vegetables and fruits are few and difficult to store. Especially in the long winter, potatoes, carrots, onions and cabbage are known by Russia as the "Four Heavenly Kings" on the table, accompanying thousands of families through the cold[9]。
In Russia, the most common way to eat onions is to eat them raw, that is, cut them into shreds and make them into vegetable salad with other vegetables, or eat them together as a side dish with steak and other staple foods, or put some raw onion shreds in hamburgers and sandwiches.The most popular barbecue roll "Saulma" on the streets of Moscow will alsobarbecue, shredded onion and pickled cucumber are put into the roll cake together, which tastes delicious.
Another way to make onions is to make soup.Russians love to drinkRed vegetable soup, also known asBorsch。The method is: cut the meat into small pieces, shred the head of red cabbage, cabbage, potatoes, onions and carrots into water, add salt, sugar and other seasonings, and then pourSour creamIt tastes delicious.In some other Russian dishes, onions are indispensable for pies, meatballs and barbecues, and even for the Russian Christmas feast.
Russians have a tradition of using onions to strengthen their health since ancient times.According to the analysis of Russian experts, a raw onion weighing 80~100g contains some vitamins and minerals that can meet the normal needs of the human body for a day.Onions can not only stimulate appetite and help digestion, but also have antiseptic, antibacterial, hypoglycemic, antihypertensive, analgesic, anti-inflammatory, antitussive, insect repellent and other functions.
Sulfur compounds in onions are powerful antibacterial ingredients, which can kill a variety of bacteria, including Streptococcus mutans, which causes tooth decay.Therefore, the doctor suggests eating half a raw onion every day, which can not only prevent tooth decay, but also help reduce cholesterol, prevent heart disease and improve immunity.
In addition to eating, onions are also considered by Russians as natural preservatives for making colored eggs.First, people draw the pattern on the white eggshell, and then apply a layer of wax three days later to protect the color on the eggshell, and then put the colored eggs into onion water to cook.The wax on the eggshell will become soft after being boiled in hot water. At this time, the wax can be wiped off with a napkin to reveal the pattern of colored eggs.An egg is finished.
Prevent and cure insomnia.If you are not disgusted with the onion flavor, you can place the chopped onion beside your pillow. Its unique stimulating ingredients will play a magical role in calming nerves and enticing sleep.
Relieve coughing.If the cough is caused by a cold, you can wrap the chopped onion with gauze and cover it from the throat to the chest, which can restrain the cough to a certain extent.
dye one 's hair.Soak the purplish red onion skin in a small amount of water. After the water changes color, it can be used to dye hair.Although this hair dyeing method does not last long, only one or two months, it absolutely does not contain any carcinogens, and can be said to be the safest hair dyeing method.[9]
