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''Vitis'' (grapevines) is a genus of about 60 species of vining plants in the flowering plant family Vitaceae.〔Wine & Spirits Education Trust ''"Wine and Spirits: Understanding Wine Quality"'' pgs 2-5, Second Revised Edition (2012), London, ISBN 9781905819157〕 The genus is made up of species predominantly from the Northern hemisphere. It is economically important as the source of grapes, both for direct consumption of the fruit and for fermentation to produce wine. The study and cultivation of grapevines is called viticulture. All vines share the same basic, physiological features. The roots anchor the vine to the soil and serve as the conduit where nutrients and water from the soil are absorbed. Along with the trunk or "permanent wood" features, the roots also serve as storage reserve of carbohydrates which the vine can use for energy in the winter after the leaves have fallen and are no longer conducting photosynthesis. The function of photosynthesis in the grapevine is to produce glucose which can be combined with other molecules to form larger carbohydrates (such as cellulose) that can be used to create other structures in the vine, energy reserves for the plant and, for fruiting grapevines, can be concentrated in grape berries which contain the reproductive seeds of the vine and are more attractive to birds and other animals.〔 Other parts of the grapevine include the tendrils which the vine uses to support itself by clinging to surrounding structures (such as the trellising of a vine-training system) and the shoots which sprout from the permanent wood and contain nodes where new leaves, flowers and tendrils can form. At the joint where leaves connect to the shoot are buds or "embryonic shoots" that contain the structures that will grow into the following years shoots, tendrils, flowers and leaves.〔 Most ''Vitis'' varieties are wind-pollinated with hermaphroditic flowers containing both male and female reproductive structures. These flowers are grouped in bunches called inflorescences. In many varieties, such as ''Vitis vinifera'', each successfully pollinated flower becomes a grape berry with the inflorescence turning into a cluster of grapes. While the flowers of the grapevines are usually very small, the berries are often big, brightly colored with sweet flavors that attract birds and animals to disperse the seeds contained within the berries.〔 Grapevines usually only produce fruit on shoots that came from buds that were developed during the previous growing season. In viticulture, this is one of the principles behind pruning the previous years growth (or "One year old wood") that includes shoots that have turned hard and woody during the winter (after harvest in commercial viticulture). These vines will be pruned either into a cane which will support 8 to 15 buds or to a smaller spur which holds 2 to 3 buds.〔 ==Biology== ''Vitis'' is distinguished from other genera of Vitaceae by having petals which remain joined at the tip and detach from the base to fall together as a calyptra or 'cap'. The flowers are unisexual or modified to act functionally as unisexual, they are pentamerous with a hypogynous disk. The calyx is greatly reduced or nonexistent in most species and the petals are joined at the summit into one unit but separated at the base. Flower buds are formed later in the growing season and overwinter for blooming in spring of the next year. There are two types of flowers produced, sterile flowers with five long filaments and erect stamens with undeveloped pistils and fertile flowers with well-developed pistils and that have five undeveloped reflexed stamens. The fruit is a berry, normally produced with four or less per flower by way of aborted embryos, ovoid in shape and juicy.〔Gleason and Cronquist volume 2, ''New Britton and Brown Illustrated Flora of the Northeastern United States and Adjacent Canada'', p. 517. 〕 In the wild, all species of ''Vitis'' are normally dioecious, but under domestication, variants with perfect flowers appear to have been selected. Most ''Vitis'' species have 38 chromosomes (n=19), but 40 (n=20) in subgenus ''Muscadinia''. In that respect the ''Muscadinia'' are the same as other ''Vitaceae'' such as ''Ampelocissus'', ''Parthenocissus'', and ''Ampelopsis''. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Vitis」の詳細全文を読む スポンサード リンク
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