The beginning of this section in the annual growth cycle the grapevine, is about six to eight weeks after that expulsion, The exact time of the year-specific temperature development that reached temperature sums depending on the location and the variety-specific growth under changing weather conditions. Constant warm temperatures with good water supply speed up the speed of shoot growth and thus the formation of the inflorescence (Latin inflorescence, depending on the country and region, also flowering, umbel, dotzen or Geschein) on the third to seventh drive node, Depending on zonalem climate, Microclimate and solar radiation, flowering takes place in the northern hemisphere from mid-May to late July (in Central Europe the beginning according to old winegrowers rule on the 24th of June = 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, greenish-yellow and rather inconspicuous because of the absence of petals and ash flowers. From the single flowers are formed with the fruit ripeness of the individual berries grape,
In the pre-bloom stage, the longitudinal axis of the inflorescence first stretches, then the lateral branches spread with the still close-packed, closed single flowers. With increasing development, the single flowers dissolve from the flower bandage, swell and turn to the green-yellowish shortly before the actual beginning of flowering. The beginning of flowering is set when, in dry, warm weather, the first perianth (perianthium), which has grown over to become a flower cap, comes loose from the flower bottom. At lower humidity the flower toads are dropped by means of a sophisticated jumping mechanism, so that the honey scented scars are exposed and the stamens can spread.
The single flowers of the cultivated vine are with most Rebsorten hermaphroditic or two-sexed. That is, they contain in a single flower both the stamen with the male gametes in the pollen grains (= pollen) as well as the ovary with the female oocytes and the scar to be pollinated (see also in detail in detail below flower bud ). The stage of full bloom is reached when about half of the flower toads have been dropped. However, the individual flowers never bloom at the same time, but in a time-delayed sequence, as well as the individual batches of the vine depending on exposition (Sunlight) and position on the fruit shoot not at the same time, but start with a time delay with the flower.
The total flowering time is normally about eight days, but it can also last up to three weeks in bad, wet-cold weather. With increasing global warming or the climate Change A trend can be noted for earlier flowering dates with shorter flowering time. The number and size of the flowers as well as the number of single flowers were already created a year earlier in the formation of the winter bud (see initiation ). On a fruit shoot are usually one to three (to a maximum of five) inflorescences in the form of a so-called panicle (actually, the term grape is not correct for the inflorescence of the vine). After flowering, pollination and...