Cvet vinove loze

Vitis vinifera, the common grape vine, is native to the Mediterranean region, Central Europe and southwestern Asia. The flowers of Vitis vinifera are small and greenish to white and are grouped in inflorescences. The grape flower has no conspicuous petals; instead the petals are fused into a green structure called the calyptra, commonly referred to as the cap. The cap encloses the reproductive organs and other tissues within the flower. A flower has a single pistil and five stamens, each tipped with an anther. The anthers produce many yellow pollen grains.

The male flower parts of grapevines are responsible for the formation of the floral scent, which consists of sesquiterpenoid volatiles. In Cabernet Sauvignon, the enzyme valencene synthase, which produces the major sesquiterpene volatiles of the flowers, is present in the anthers. Transcripts of the valencene synthase gene are most abundant in flowers at prebloom stages. (+)-Valencene, (E,E)-α-farnesene and (-)-7-epi-α-selinene are the most prominent sesquiterpenes in these emissions, making up to 60% of all volatiles released at the height of emissions. During bloom, a Cabernet Sauvignon flower emits volatiles at a maximum of up to 1,047 (± 504) pg per hour. Aliphatic compounds made up as much as 16% of total emissions at the time of maximum release.

More than 50 volatile compounds have been identified in the flowers of Vitis vinifera varieties growing in Sicily. Sesquiterpenes, together with monoterpenes such as limonene and cymene, are the principal components. The odour profiles make it possible to tell variety groups, or even single varieties, apart.

Valencene is obtained inexpensively from Valencia oranges. It is used as a precursor to nootkatone, the main contributor to the aroma and flavor of grapefruit.

Before budburst each fine-branch meristem produces clusters of three to four flower primordia, and a calyx forms. After bud burst the corolla and the stamens appear first, then the pistil, ovaries and ovules. Fertilization occurs within 12 hours at 25-30 °C, takes 24 hours at 20 °C and 48 hours at 15 °C.

Bloom, the period during which the flowers are open, can last from 1 to 3 weeks depending on weather conditions. Bloom typically occurs between 50 and 80 days after budburst. Cool temperatures can delay and extend the bloom period, which can run over 3-4 weeks in Mediterranean climates with mild winters. The anthers may release their pollen either before or after cap fall. The wild vine is dioecious, with male and female flowers on different plants, whereas the cultivated forms are hermaphroditic.