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The crucial and most important section in the annual Vegetation cycle of Vine . The onset is about six to eight weeks after the shoot bud. The exact time depends significantly on the year-specific temperature evolution, the locally already reached temperature sums at the particular location and the varietal-specific growth response to changing weather conditions. Constant warm temperatures accelerate the speed with good water supply of shoot growth and thus correlated with the formation of the inflorescence shoot growth (Latin inflorescence, and Bloom, umbel, or dotzen Geschein) at the third to seventh driving nodes. Depending on the zonal climate, microclimate and Sunlight takes place the bloom in the northern hemisphere from mid-May to late July (in Central Europe, the beginning is the old wine generally to June 24 = St. John's, plus or minus eight days), except for the southern hemisphere from November to mid- December. Unlike many other flowering plants are the single flowers of the vine small, yellow and green because of the absence of petals and flower show generally rather inconspicuous. Some ten thousand of these to form a single flower racemose inflorescence, from which the fruit ripens, the Grape developed.
In Vorbl├╝testadium extends initially the longitudinal axis of the inflorescence, then the lateral branches spread with the still-tight manner to dense, closed single flowers. With increasing development, the individual flowers emerge from the flower association, swell and change color just before the actual onset of flowering in the green-yellow. The onset of flowering is recognized when dissolve in dry, warm weather, the first flowers to a cap fused petals from the receptacle. At low Humidity the flowerhoods fallen by a jumping mechanism, so that the honey-scented scars are exposed and can splay the stamens. The individual flowers of Kulturrebe are usually built hermaphroditic, meaning that they contain in a single flower, both the stamens of the male gametes in the pollen grains (= pollen) and the ovary of the female egg cells and to be dusted scar. The stage of full bloom is reached when about half of the flower cap was dropped. However, the individual flowers bloom at the same time from inflorescences never, but in a slightly time-delayed sequence, as well as the individual does not Gescheine the vine depending on solar radiation and fruit position on the same engine, but start with a time delay of flowering.
The Gesamtbl├╝hdauer is normally about eight days, they can last in bad, wet and cold weather but also up to three weeks. With increasing global warming and the Climate Change is a trend to earlier flowering refills find a shorter flowering period. The number and size of flower, as well as the number of individual flowers have already been created a year ago in the formation of winter buds (see Initiation ). Fruit on a train are usually one to three (maximum five) inflorescences in the form of a so-called Panicle (Actually that is the name of the grape inflorescence of the vine is not correct). After flowering, pollination and fertilization, successful development of the ovary to the grape berry and Geschein. Each cluster consists of a few dozen up to 600 berries, but it is the fertilization success depends on whether in fact from the maternal tissues of the ovary ripens a berry or whether as in bad Bl├╝hwetter pollination and fertilization process is suffering, remain the berries jungfernfr├╝chtig or already as unfertilized flowers on the flower fall off easily and Coulure .
Most of the people cultivated grapes (Vitis vinifera sativa) are hermaphroditic and monoecious, which means they have hermaphrodite flowers with fully functional male and female sex organs on each vine. However, there are varieties with Although functionally female flowers, which were but the stamens reduced or totally sterile. This is often the case with table grape is the case (see also under vines female ). These varieties are, however, necessarily depends on a cross-pollination, so their earnings greatly depending on flowering conditions and fertilization success varies. In seedless varieties like korinthiaki or Sultana , the female sex organs are infertile. Without the fruit of the growth-stimulating seed set the berries remain small and stunted, but they are suitable for the production of seedless Dry berries. The growth in size of seedless grapes can be artificially induced by growth hormone (see Gibberellins ).
In contrast, the Wild Vines (Vitis vinifera sylvestris) is usually dioecious. Every once for wild grape seedling grown-up bears either male or female sexual organs. The Eingeschlechtlichkeit is secondary in nature, because both bodies present in the vine as an investment, but are only ever a sex organ is formed functional while the other is suppressed hormonally. In dioecious plants self-fertilization is impossible in principle and the fertilization of the female plants can only scars by cross-pollination with pollen from another vine performed with male stamens. This is an evolutionary process-promoting in nature, in order to get through the recombination of genes of forced paternal and maternal plant genetic diversity in a wild population and thus to facilitate adaptation to environmental changes (see also under Heterozygosity = Spalterbigkeit). In the vineyard, but this is not desirable because of the uncertain returns. Many as a base and rootstock varieties used are hybrids of wild vines and thus dioecious. In the Breeding of documents are preferred varieties with male flowers, which make less work for the lack of grapes.
A Selfing (self-fertilization) is usually avoided by nature, since only the cross-pollination evolution and the survival guaranteed. This means that the scars are self-sterile female by chemical, mechanical and physiological mechanisms for the male's pollen. At Wild Vines is avoided by the separation-sex (dioecious). The cloning of individuals in nature is not so provided. In crop plants this self-sterility mechanisms have been bred out often wholly or partially. In the fruit and seed formation grapes scaffolding, grape skin and soft flesh, and formed the seed coats with the supply of tissue for the embryo of the Mutterrebe. Only the embryo in the grape seed is the result of sexual pollination and fertilization processes. This means that the cluster is unaffected. Riesling Riesling is, even if the fertilization was carried out by Sylvaner. If the seeds are germinated and then grow into a vine, which would thus created Seedling spontaneous crossing of two parent plants and products introduced each a new variety dar. fremdbefruchtete varieties are usually more fertile and more vital than seedlings from self-fertilization. In this way are in thousands of years, countless varieties developed spontaneously.
The Kulturrebe autogamous but is optional, which means that it can fertilize itself very well. Hermaphroditic plants of each variety can be pollinated with pollen from plants of the same species or other species and fertilized successfully, without this circumstance suffer the fruit set. However, the germination of the seeds of self may be affected. But this is irrelevant, because the wine grapes are not for the grapes and their seeds for sowing. For berries and fruit formation, it is sufficient, however, when pollen grains fall on the sticky scars of neighboring flowers and Gescheine. The pollen grains are as mentioned here mostly from the same or an adjacent vine. You can also just come from a different species from a neighborhood wine garden. The wind is involved in pollen transfer to a considerable extent, while the seeds can fly several hundred meters wide. Similarly, the transfer from the scent of flowers attracted insects such as Bees the pollen grains from one flower to another. In principle, however, must not be cross-pollinated and Kulturrebe is not like many other dioecious plants and the wild vines thus dependent on the presence of insects or other fertilization fertilizing agents. This is crucial for the stability of yield. No matter come from where also produces the pollen grains from the anthers on the sticky stigma, they get stuck there (pollination), germinate and form the pollen tube which grows into the stigma and the style to fertilize one of the four eggs in the ovary.
The maternal tissue of the ovary is growing in the sequence to zoom berry, which contains one or two to four fertilized seed or grape seeds. Prevails during flowering vines bad weather such as cold, rain, wind or Hail before, the pollination and fertilization process may be impaired. Rain, wind and high humidity hinder the distribution of pollen and pollen to produce, but also that the jump mechanism keeps the cap does not or only partially, and they will not be blown off or fall off, but loose on the scars and stick there. Then can be no more pollination. Cold also hampered the growth of the pollen tubes. As a result, never fertilize all ovules. As the embryo in the seed, however, stimulated the formation of the fruit, which remain insufficiently fertilized berries smaller. The result is an early or Jungfernfr├╝chtigkeit Coulure (drop) of the completely unfertilized flowers. The bunch then has fewer and smaller berries (see also Kleinbeerigkeit ). This is not necessarily a disadvantage, because a reduced yield increases in the quality control. Because the produced ingredients are now focusing on a smaller number of berries, and more can extract a higher sugar content and better overall quality of wine results. A few weeks after flowering the berries reach pea size. This includes but is already developing the next step, the Fruit set .
The fertilization of the cultivated vine is also detailed in Hermaphrodite flowers described. See also the morphology of grapevine in Eye , Leaf , Flower bud , DNA , Molecular genetics , classification Vines , Grape , Vine , Shoots and Breeding .