Common flax ( Linum usitatissimum )
Common flax ( Linum usitatissimum ), also known as seed flax or flax , is an old cultivated plant that is grown for fiber ( fiber flax ) and oil (oil flax , flaxseed , flax oil ). He is a kind from the kind flax ( Linum ) in the family of Flax Family (Linaceae) and the only flax species whose cultivation has an economic importance. There are several varieties as well as several varieties. In practice, a distinction is made between fiber flax and oil flax according to the main use.
The common flax is an annual plant ( therophyte ) that reaches a height of 20 to 100 centimeters. It has a short, spindle-shaped taproot with fine side roots. The main root becomes about the same length as the shoot. The whole plant is bare. The stems are mostly single and upright, in the area of the inflorescence they are branched.
The stalkless leaves are alternate. They are two to three (rarely four) inches long and 1.5 to three (six) millimeters wide. Their shape is linear-lanceolate, with a leaf five to 15 times as long as it is wide. The leaves are three-veined, glabrous and have a smooth edge.
Stems and fibers
The outermost tissue in the stem is the epidermis covered by a layer of wax . This is followed by the chlorophyll- bearing bark layer . Embedded in the bark layer are 20 to 50 bast fiber bundles as a reinforcement fabric. Each bundle consists of ten to 30 sclerenchyme cells, the elementary fibers . These have a hexagonal to polygonal cross-section with a small cavity. The length of an elementary fiber is on average 2.5 to six centimeters, in the upper parts of the stem it can also reach eight to ten centimeters. The whole fiber bundle is called technical fiber. The fiber content of the stem is 19 to 25%. The fiber itself consists of 65% cellulose , the other components are hemicellulose with 16%, pectin (3%), protein (3%), lignin (2.5%), fats and waxes (1.5%), minerals (1%) and 8% water.
Towards the inside follows the very thin cambium , then the largest area, the wooden cylinder . In the center there is a narrow area made of pith , and in the mature stem there is still a cavity (lumen, 1).
Inflorescence and flowers
The inflorescence is a panicle-like coil . The flowers are large and over two inches wide. The flower stalks are longer than the bract , glabrous and upright. The flower is five-fold. The sepals are five to seven (nine) millimeters long. They are long, pointed, have a white skin edge and are ciliate at the tip. The sepals are three or five nerved. The petals are 12 to 15 millimeters long and light blue in color with darker veins, rarely white, purple or pink. The five stamens are two to five millimeters long and have nectaries at their base . The ovary is on top and consists of five intergrown carpels with free styles . The scars are club-shaped. In terms of flower biology, it is a homogeneous , nectar-bearing disc flower . Self-pollination (autogamy) is predominant, cross - fertilization by insects (outcrossing rate) is around five percent.
The flowering period is June, July, August.
Fruits and seeds
The fruit stalks stand upright and carry a six to nine millimeter long capsule . This is spherical-egg-shaped and beaked around one millimeter long. The capsule has five compartments, each compartment contains two seeds. Each compartment is divided into two compartments with one seed each by a false partition. The capsule opens with a wall or gap or remains closed.
The seeds are 4 to 4.9 (6.5) millimeters long and 2.5 to three millimeters wide. The shape is flattened ovoid. The navel (hilum) is at the narrow, pointed end. The color of the seeds varies, depending on the variety, from light yellow to dark brown with a shiny, smooth surface. The thousand-grain mass of flax fiber is four to seven grams, and oil flax up to 15 grams. The seed coat is thin, brittle and consists of five layers: The epidermis forms mucilage. This is followed by a layer of cells, ring cells, stone cells and transverse cells. The innermost layer, the pigment layer, is single-celled and consists of four- to hexagonal, thick-walled cells and is responsible for the color of the seed. The endosperm is weak and only present in the form of a thin membrane. Like those of the cotyledons, the cells contain oil and protein. The embryo has two strong, fleshy cotyledons that serve as storage organs.
The oil content of the seeds is between 30% and 44% and depends on the variety, the environmental conditions and the degree of ripeness. Since flax fiber is harvested before it is fully ripe, its seeds contain less oil. The main fatty acid is the unsaturated α-linolenic acid with around 50% to 70% . The content of omega-3 fatty acids, which are important for human nutrition, in linseed oil is the highest of all known vegetable oils. The other composition is 10% to 20% linoleic acid , 12% to 24% oleic acid , and less than 10% stearic and palmitic acid . The crude protein content is between 19% and 29%. The proportion of the amino acids lysine , methionine and tryptophan , which are essential for humans , is high. The secondary ingredients are the cyanogenic glycosides linamarine and lotaustralin , which can be enzymatically converted to hydrocyanic acid and can therefore cause poisoning if large amounts are consumed.
The number of chromosomes is 2n = 30 or 32.
The germination of the flax is epigeic . At the beginning of germination, the seed swells up under water absorption, whereby the mucous epidermis enlarges many times over. The seed coat opens at the pointed end (hilum) by breaking through the radicle (radicula). Then the hypocotyl stretches and the cotyledons , which are still folded at the beginning, unfold and turn green. The cotyledons continue to grow and remain for several weeks.
The tip of the shoot between the cotyledons grows into what is often a single stem. With oil flax, and also with fiber flax in loose stocks, a basal branching takes place in the axils of the cotyledons with the appearance of the third pair of leaves.
Growth is relatively slow up to a height of around eight centimeters, after which it accelerates. In many varieties, the stem continues to grow in length until the end of the flowering phase. The number of leaves is highest at the beginning of flowering, with the beginning of the seed filling the death of the oldest leaves begins.
The flowers are budded relatively early, around one sixth of the maximum height of the plant, with fiber flakes around 15 centimeters. The tip of the shoot tilts downwards, the buds appear and the flowers appear a few days later. The number of flowers is not determined, depending on the variety and environmental conditions, the inflorescence is branched differently. Flax is a long-day plant , the critical day length is 14 to 16 hours. Short day conditions lead to a longer stem length and a later start of flowering. Therefore, early sowing is beneficial so that as much stem mass as possible can be formed during short days.
It blooms from June to August. The flowering period of the stand from the opening of the first to the closing of the last flower takes about two weeks for fiber flax. The bloom begins with the terminal bloom of the main shoot tip. The single bloom begins in the early morning. When the flower is still closed, the anthers open and apply the pollen to the stigma with a twisting motion. The self-pollination is done so prior to the opening of the flower, which takes place in the morning. Small nectar glands at the base of the stamens attract insects . Shortly after the flower has opened, the petals are shed, the sepals enlarge and contribute to the supply of the young seeds. The sepals remain until the fruit is ripe.
Flax does not make any special demands on the soil, it only does not tolerate waterlogged, silt-prone and boggy locations. Long-day conditions are necessary for flower formation and fiber growth. Dry periods significantly reduce the number of fiber bundles, the water requirement of linen is less than that of linen. A good water supply of around 120 millimeters of precipitation in the main growth phase in May / June is important.
In the crop rotation , a gap of six years is necessary between two linseed crops. This is due to the accumulation of harmful fungi, especially Fusarium oxysporum , in the soil. Otherwise, flax does not make any special demands on crop rotation. It is important to have a previous crop that leaves little weeds. The best previous crop is seed oats , in France and Belgium flax is often grown after maize .
As a long-day plant, flax requires early sowing, usually at the end of March / beginning of April. Occurring late frosts are tolerated, but intensify the basal branching, which for fiber flax reduces the yield and quality, is tolerable for oil flax. The main crop - fiber or oil - can be influenced not only by the choice of variety but also by the crop density: low densities promote seed formation, high crop densities promote fiber formation.
Fertilization is usually limited to the application of phosphorus and potassium , with oil flax a single nitrogen application is made. Too much nitrogen increases the risk of storage considerably and also leads to poorer fiber quality: the fiber cells become more spacious and thin-walled, the fiber bundles are loose and irregular and more lignified. With oil flax, too much nitrogen leads to a lower oil content and a lower proportion of linolenic acid. Above all, a good supply of potassium increases the fiber quality: the size, strength and spinnability of the fiber improve, and the number of fiber cells increases. Chlorides lead to a loosening and a spongy structure of the fibers, which is why fertilizers containing chloride are not suitable. The magnesium requirement is relatively high with a withdrawal of 18 kilograms per hectare. Boron and zinc are particularly important micronutrients . During the dew rust that takes place in the fields, a large part of the nutrients absorbed are returned to the soil.
Flax fiber requires special machines for harvesting. The harvest takes place at yellow maturity, i.e. seven to ten days before full maturity. The plants are pulled up in bundles with a scraper, that is, they are pulled out of the ground with the roots. This is followed by the further processing steps such as roasting, breaking, swinging and panting. On average, 5 to 6 tons of roasted straw are harvested per hectare. (see flax fiber # harvest )
Cultivation areas and harvest quantities
|Flaxseeds harvested in
2006 (in tons)
|People's Republic of China||480,000|
The largest growing countries for flax outside the EU are (with acreage in hectares in 2005) China with 161,000, Russia with 89,210, Belarus with 71,000, Ukraine with 23,600 and Egypt with 8900 hectares. In 2006, 102,740 hectares were cultivated with processing aid in the EU, whereby the areas without processing aid are negligible. Of this, France has 76,278, Belgium 15,919, the Netherlands 4,366 and the Czech Republic 2,736 hectares. In Germany with 30 and Austria with 129 hectares the cultivation is meaningless.
Up until the 2012 financial year, the EU still subsidized the production of short fibers with 90 euros per ton. For the traditional growing countries of the Netherlands, Belgium and France, there were additional area subsidies of 50 to 120 euros per hectare until 2007/08. The processing aid for long fibers was also abolished in the 2012 marketing year. Until 2010 it was 200 euros per hectare, until 2012 it was 160 euros. The world production of flax fibers is around two million tons annually, which corresponds to around two percent of the world fiber volume.
The linseed oil is mainly grown in North America. The annual harvest quantities fluctuate considerably from year to year and in the main cultivation country, Canada, were between 517,000 and 1,082,000 tons of flaxseed between 1996 and 2005. The most important growing provinces are Saskatchewan and Manitoba , there are also small areas in Alberta . According to the FAO, the world harvest in 2006 was 2,569,793 tons.
Competition, diseases and predators
Young populations are relatively weak, so weeds play a role: Field pansy ( Viola arvensis ), common shepherd's purse ( Capsella bursa-pastoris ), chamomile ( Matricaria recutita ), black nightshade ( Solanum nigrum ), white goose foot ( Chenopodium album ), bindweed ( Fallopia convolvulus ), bird knotweed ( Polygonum aviculare ), forget-me-not ( Myosotis spp.), Chickweed ( Stellaria media ), common windstalk ( Apera spica-venti ) and chicken millet ( Echinochloa crus-galli ). Some of the earlier for flat fields typical "linicolen" weeds such as the parasitic flax dodder ( Cuscuta epilinum ) of linseed ryegrass ( Lolium remotum ), perforated camelina ( Camelina alyssum ), a subspecies of the corn cockle ( Agrostemma githago var. Linicolum ) and flax - Gluewort ( Silene linicola ) are practically extinct in Central Europe due to the long break in cultivation.
The main pathogens in flax are fungi . In Western Europe, the most important disease is flax wilt or fusariosis caused by Fusarium oxysporum f. lini . It destroys the pathways and excretes wilt toxins, whereupon the plants wither and die. Other diseases and agents in Lein are the flax rust ( Melampsora lini ), the Pasmokrankheit ( Septoria linicola ), the brown spot or anthracnose ( Colletotrichum linicola ), Stem tan and stem breakage ( polyspora lini ), Pustelkrankheit and stems drought ( Phoma linicola and Ascochyta linicola ) as well as the flax or root blight ( Pythium megalacanthum ). The fungal diseases of gray mold rot ( Botrytis cinerea ), black fungi ( Alternaria ) and powdery mildew ( Oidium lini ) are less dangerous because they are easily treatable. Viruses transmitted by aster leafhoppers can also be of concern in North America . The rust fungus Melampsora liniperda also attacks the common flax.
Among animal pests, linseed fleas ( Aphthona euphorbiae , Longitarsus parvulus ) are the most important, as they damage plants by eating. There are also linseed bladder feet ( Thrips linarius and Thrips angusticeps ).
Late frosts are important abiotic factors, as they can lead to the complete death of the seedlings. Chlorosis can occur after excessive limescale, as this indirectly causes an iron deficiency.
Processing and use
The processing of the flax fibers is complex. The flax stalks are first roasted , whereby the bast fibers are loosened by microorganisms in the water (water roasting) or lying on the field (dew roasting). After roasting, the flax is broken, which breaks up the wood and creates the shives . The linen is then swung, in the process the tow , which contains short fibers , is separated from the high-quality long fibers . Around 15% of the stem mass are long fibers. These are cleaned by panting and then spun. About 61% of the production of flax fibers is used to obtain long fibers.
Linen fibers, for which long fibers are used, have a market share in textiles of less than one percent. Around 40% of the linen is used for clothing, 25% for household linen, 20% for home textiles and 15% for technical purposes.
The tow (short fibers) created as a by-product can be processed into paper. It is used in upholstery fillings, composite materials and insulation materials. The shives are processed, among other things, in pressboard as a filler, and also used as animal bedding. The linseed wax falls in the dust, can be easily isolated and is used in the cosmetics and pharmaceutical industries.
The seeds are used from both flax and fiber flax. The flaxseeds are only used to a small extent directly in baked goods, as health food and as a medicine for constipation. Other medical applications are not sufficiently scientifically proven. The majority is used for oil production. Linseed oil can be used as an edible oil. The linolenic acid content of 50% to 67% makes it a drying oil. In industry it is processed into paints, varnishes, varnishes, printing inks, oilcloths, soft soap and linoleum and used in the manufacture of cosmetics and care products. In paints and varnishes it has been largely replaced by synthetic products, but is still used today in printing inks and for varnishes and varnishes in wood protection. By-products of oil extraction are flax cakes and flax meal, because of their richness in protein they are used as animal feed, especially for cattle and calves.
The common flax is only known from culture. Only rarely does it appear wild. It comes from the two-year-old flax ( Linum bienne ), which is native to the Mediterranean region. This species was cultivated in Mesopotamia from the early Neolithic (from 7,500 BC). The origin of the common flax is likely to have occurred in Mesopotamia or Egypt. The two species are also listed by some authors as subspecies of the species Linum usitatissimum , the two-year-old flax is then Linum usitatissimum subsp. angustifolium (Huds.) Thell. and the common flax Linum usitatissimum subsp. usitatissimum .
The systematics within the species has long been controversial due to the great variability of flax. Between 1866 and 1953, at least eight systems for cultivated flax were proposed. In 1962 Kulpa and Danert published an outline in which they used the cultivated flax as a subspecies Linum usitatissimum subsp. usitatissimum into four varieties , and these in turn into a total of 28 varieties. The editors of Mansfeld's Encyclopedia of Agricultural and Horticultural Crops , as well as Diederichsen and Richards 2003, have also subscribed to the division into the Convarieties .
- Convar. crepitans (Boenningh.) Kulpa & Danert : The capsules open during ripening and the seeds fall out of the capsule. When they are mature, the capsules are discarded. The sound of jumping up led to the name Klanglein, it is also called Springlein. This convariety was previously grown as a fiber plant in Central and Southeastern Europe. It is no longer grown commercially and is only preserved in seed banks.
In the other convarieties, the capsules remain closed when ripe and are not discarded.
- Convar. elongatum Vavilov & Elladi in E. Wulff : The plants are taller than 70 centimeters and at most the top third of the trunk has side branches. If the plants are less than 70 centimeters high, at most the top fifth is branched. This variety is the typical fiber flax and used to be of great importance in the temperate and northern areas of Europe, especially in Eastern Europe, and is still grown today in the Western European fiber flax countries.
- Convar. mediterraneum (Vavilov ex Elladi) Kulpa & Danert : The plants are smaller than 70 centimeters and branched in more than the upper fifth. The thousand grain weight is more than nine grams, the capsules are large. As a rule, the plants are not branched at the base. The varieties of this convariety are known as linseed and are used only to produce seeds. This convariety comes from the Mediterranean region and has a relatively long vegetation period. The oil flax is grown for the production of the flax seeds, the fiber production is secondary.
- Convar. usitatissimum : The plants are smaller than 70 centimeters and branched in more than the upper fifth. The thousand grain weight is less than nine grams. The plants are often branched at the base. This convariety includes the combination lines that are grown for fiber as well as seed production. It is the geographically most widespread convariety and includes, among others, the spring seed, winter seed, the Indian and the Ethiopian flax.
Only fiber flax and oil flax are important for commercial cultivation. There are a large number of varieties of both. Attempts to introduce a combo that should provide both high quality fiber and flaxseed have been unsuccessful.
In the EU 120 types of linseed oil and fiber are permitted for cultivation, in Austria as of 2008 the varieties: 'Barbara', 'Hungarian Gold', 'Omega' and 'Sandra' as linseed oil; as fiber 'Laura'.
The oldest archaeological linseed finds come from Ali Kosh in Iran (7500–6700 BC) and from Çayönü in southeastern Turkey (around 7000 BC). However, the flax seeds are so small that they are classified as wild flax ( Linum bienne ). In Tell Ramad in Syria, in a period from 6200 to 6100 BC Linseed, which is closer to the size of the common flax, was found in the settlement layer dated to the 4th century BC. Other early sites are on the upper reaches of the Tigris , in the foothills of the Zāgros Mountains and in Syria . A site in Greece ( Sesklo , Peloponnese ) is dated 5500 BC. Dated, two sites in Bulgaria to 4800 and 4600 BC. Genetic studies have shown that the common flax is descended from the wild flax through a single domestication event. According to these studies, the first use was to use the seeds.
The oldest finds of linen processing are linen fabrics from Egypt from the beginning of the 4th millennium BC. They come from El Badâri in Upper Egypt. From 3500 to 3000 BC The linen cloth from el-Gebelên in the Libyan desert is dated. From the 4th dynasty, mummy bandages made of linen have been preserved. Pictorial representations of the flax harvest also come from the Old Kingdom . Seeds and capsules have been found several times as grave goods from the Middle Kingdom.
Flax came to Central Europe with the band ceramic culture (approx. 5700 to 4100 BC), it was grown on the loess areas north of the Danube as far as northern France. In the bank and pile dwellings on Lake Constance and the Swiss lakes, flax was introduced a little later. After Ireland and Scotland the flax came about around 1800 v. In northern Germany and Scandinavia it is only from the Iron Age, from around 500 BC. Detectable, but flourished during the Roman Empire (1st to 3rd century AD).
In the Middle Ages, flax was listed in all agricultural and medical directories. Common flax was called Lini semen in the form of a seed drug . In the Middle Ages until the 19th century, linen was used as a textile fiber alongside hemp , nettle and wool . Production and trade in linen were important economic pillars in Venice , Milan , Augsburg , Ulm , Kempten and in Ghent , Bruges and Antwerp in the Middle Ages and early modern times . Linen products were also an important branch of trade for the Hanseatic League . The most important German cultivation areas were around Lake Constance and Silesia and spread to the Swabian Alb , Wuppertal , the areas around Ravensburg and Osnabrück , Saxony , Thuringia , Bohemia and East Prussia . In the 12th and 13th centuries Germany was the world's leading flax producer. The linen production was concentrated in Silesia, Swabia and Westphalia.
In the 18th century, linen was about 18% compared to 78% for wool. Important growing areas were Western Europe, Germany and Russia . In 1875 the three largest cultivation areas were the Russian Empire with 910,000 hectares, the German Empire with 215,000 and Austria-Hungary with 94,000 hectares. With the advent of cheaper and, above all, easier to process cotton , the area under cultivation fell sharply in the 19th century. In 1914 only 14,000 hectares were cultivated in Germany. The cultivation experienced a brief increase during the two world wars, when cotton imports were not possible due to the political situation. In the post-war period, flax cultivation fell sharply and had disappeared in 1957 in West Germany and 1979 in East Germany, with the exception of a small amount of remaining land. In Western Europe, cultivation lasted only in northern France, Belgium and the Netherlands.
In the 1980s, with the ecology movement, the demand for linen increased.
In the 1990s, efforts were made in some EU countries to revive flax cultivation and production. The focus was on short fiber production. Thanks to subsidies, the cultivation area increased to 212,000 hectares in 1999. Marketing problems on the one hand and stricter controls with regard to the actual production and marketing of the fibers on the other hand led to a decrease in cultivation areas in these "new" flax countries (Spain, Portugal , Great Britain, Germany). Spain paid back the full funding amounts from 1996 to 1999 in the amount of almost 130 million euros. Today, flax cultivation is again essentially limited to the traditional countries of France, Belgium, the Netherlands and the new EU member states of the Czech Republic, Latvia and Lithuania .
In 2005 flax was the medicinal plant of the year in Germany .
In 2009, inspections of Canadian linseed in Baden-Württemberg found significant contamination with genetically modified CDC Triffid linseed.
The success of the well-known Czech cartoon series The Little Mole began in 1957 with the film How the Mole Got His Trousers , in which the processing of flax is shown in detail.
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