Sunflower

Description

It is a large annual plant, with very strong and little ramified Tige, being able to reach up to 4 m height. The Sheet S simple, oval, alternate, except at the base where they are sometimes opposite, have a more or less long petiole and are hard with the touch. The flowerheads, floral receptacles fleshy, which tend to be reversed after flowering, can reach 30 cm of width. They are surrounded by a Involucre with Bractée S ovals with a pointed top. The external Fleur S ligulées laid out on only one row, are generally yellow. The central flowers out of tube are yellow pale or red dark at the anthocyanées varieties. The fruits are Akène S surmounted by two scales in edge. The principal root is swivelling.

The provision of the central flowers (or florets), or of seeds, on the receptacle draws spirals answering the rules of the Phyllotaxie and turning either in the direction of the needles of a watch, or in opposite direction. The numbers of florets of each type of Spirale are constant and are successive numbers of the Suite of Fibonacci, for example 34/55 or 55/89.

The sunflower is prone to the heliotropism before flowering. This phenomenon acts on the growth of the stem according to illumination. It makes it possible the sheets to keep throughout the day an optimal exposure to the sun. At the beginning of flowering, the flower points definitively in the direction South-eastern East/.

Origin

It is a plant originating in the West of the North America: is Canada and the United States, center and south of the United States, north of the Mexico. Cultivated originally by the Amerindian S, it was imported in Europe by the Spaniards at the 16th century. Its culture developed particularly in Russia. It today is largely spread by the culture in all the continents.

To note that the kind Helianthus includes/understands about fifty species, all originating in North America, of which the Topinambour ( Helianthus tuberosus L.)

Use

Human consumption

The oil is extracted from the seeds, whose content in the improved varieties varies from 45 to 50%. The sunflower oil is appreciated for its balance in fatty-acids: it contains 12% only fatty-acids saturated and much with fatty-acids mono or poly-unsaturates, Acid oleic, Palmitic acid and especially Linoleic acid, which is a essential Fatty-acid. According to the nutritionnists, this oil has excellent dietetic qualities, for example to fight the diabetes. It is also a good source of Vitamine E. The sunflower oil uses the composition of the Margarine S. It is also used with manufacture of soap and candles.

One consumes also the torrefied seeds .

Animal feeds

The whole plant collected before maturity is used like Fourrage. Moreover, the residues of trituration, called oil cakes, are rich in Protéine S, including one Amino-acid very required in the food of the Bétail, the Méthionine. The whole seeds are appreciated to nourish the Perroquet S and others Oiseau X of birdcage.

It is also a plant Mellifère, but it with the disadvantage of flowering late in season.

It is also cultivated as plants decorative for its spectacular flowerheads. There exists about it several cultivars, in particular “Nanus flora pleno”, from 60 to 80 cm in height only and double flowers orange yellow.

Biocarburant S

The sunflower oil, as the oil of Colza, can be used directly like Biocarburant in the diesel engines, or after methyl ester esterification. Beyond 30% of HVP (pure plant oil), it is advisable however to make certain adjustments (pressure of injection) and possible modifications (pre-heating). The experiments with 100% of HVP on the heavy trucks generally function with a system of starting to the gazoil. Pure oil, contrary to diesters, does not require any industrial process of manufacture. A simple press is enough. The sunflower is the plant which offers the best output (six times superior with the gazoil). It is also most ecological. No the rejection of suffers, 25% of emission of derivatives nitrogenized in less, three times less CO rejected with combustion… Politically, the application of the TIPP to the HVP, voted at the end of 2006 by UMP, makes the HVP of sunflower more expensive than the gazoil, thus leading the experiments in progress like that of Villeneuve on Lot (Batch & the Garonne), in contradiction with the European directives preaching a gravitational taxation for the bio-fuels. However, the farmers can produce HVP and use it at their personal ends without having to pay of tax, which lets fear the development of pirate networks of distribution.

Culture

To push, the sunflower has very important thermal needs for a plant originating in the moderate areas; able to be satisfied with little water, he suffers however in the event of dryness in not irrigated culture; that explains why its zone of culture is in particular in southernmost Europe. He also needs Azote and Potassium. It is a plant with cycle of culture runs; it is sown about April/May and is collected about September, and does not exhaust the ground. The development of the culture of the sunflower in France, like that of the Colza, as from the years 1970 is with the need for independence of the European Community vis-a-vis the monopoly of the United States as regards oilseeds. The development of new varieties (by crossing and selection), in particular of hybrids resistant to the mildew, contributed to the development of the culture of the sunflower during the twenty last years, in particular in France. Today, it is cultivated in South-west, the Center and in Coast-in Or.

Enemies of the cultures of sunflower

In addition to the very fond of delicacies birds of its seeds, in particular the domestic Sparrow, the verdier and the Linnet, the other ravageurs notable are the gray slug, the tipule meadows ( Tipula paludosa ) and the Thrips of the tobacco ( Thrips tabaci ) which attacks the young seedlings, and the green Puceron of the plum tree ( Brachycaudus helichrysi ) which attacks the sheets.

The principal diseases met are the white rot ( Sclerotinia sclerotiorum ), the Mildiou of the sunflower ( Plasmopara helianthi ), appeared in 1978, the Alternariose ( Alternaria helianthi ), the Verticilliose ( Verticillium dahliae ), as well as the Phomopsis, ( Phomopsis helianthi ), mushroom appeared in France in 1984.

It also is very attacked by a parasitic plant, the Orobanche, in the countries of the South (Spain, Turkey).

Economic importance

The world seed harvest of sunflower rose in 2003 to 26,1 million tons. (Source FAO)

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