The beginning of this section in the annual growth cycle the grapevine, is about six to eight weeks after expulsion, The exact time of the year-specific temperature development, the reached temperature sums depending on the respective location and the vine-specific growth under changing weather. Constantly warm temperatures with good ones water supply accelerate the speed of the shoot growth and thus the formation of the inflorescence (Latin inflorescence, depending on the country and region also bloom, umbel, dotzen or appearance) on the third to seventh drive node, Depending on the zonal climate, Microclimate and sun exposure will flower in the northern hemisphere from mid-May to late July (in Central Europe, according to the old winegrower rule, the start falls on June 24th = St. John's Day, plus or minus eight days), in the southern hemisphere from November to mid-December. In contrast to many other flowering plants, the single flowers of the vine are small, green-yellow and rather inconspicuous due to the lack of petals and petals. With the ripening of fruit, the individual berries of the grape,
In the pre-flowering stage, the longitudinal axis of the inflorescence first stretches, then the lateral branches spread apart with the closed single flowers still close together. With increasing development, the individual flowers separate from the flower cluster, swell and change to green-yellowish just before the actual start of flowering. The beginning of flowering is set when, in dry, warm weather, the first petals (perianthium) that have grown together into a flower cap detach from the flower base. At lower humidity the flower caps are thrown off using a sophisticated jumping mechanism, so that the scars scented with honey are exposed and the stamens can spread out.
The single flowers of the vine are common to most grape varieties hermaphroditic or bisexual. This means that in a single flower they contain both the stamens with the male gametes in the pollen grains (= pollen) as well as the ovaries with the female egg cells and the scar to be pollinated (see also in detail under flower bud ). The full bloom stage is reached when around half of the flower caps have been dropped. However, the individual flowers on the plants never bloom at the same time, but in a somewhat staggered sequence, just like the individual plants on the vine, depending on the time exposition (Sun exposure) and position on the fruit shoots do not start at the same time, but with a delay in flowering.
The total flowering period is usually around eight days, but can also take up to three weeks in poor, wet and cold weather. With increasing global warming or climate Change there is a trend towards earlier flowering dates with shorter flowering times. The number and size of the banknotes as well as the number of single flowers were created a year earlier when the winter bud was formed (see below initiation ). On a fruit shoot there are usually one to three (up to a maximum of five) inflorescences in the form of a so-called panicle (So actually the name grape is not correct for the inflorescence of the vine). After flowering, pollination and fertilization, the ovary develops into a...