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The blackcurrant (scientific name ''Ribes nigrum'') is a woody shrub in the family Grossulariaceae grown for its piquant berries. It is native to temperate parts of central and northern Europe and northern Asia where it prefers damp fertile soils and is widely cultivated both commercially and domestically. It is winter hardy but cold weather at flowering time during the spring reduces the size of the crop. Bunches of small, glossy black fruit develop along the stems in the summer and can be harvested by hand or by machine. The fruit is rich in vitamin C, various other nutrients, phytochemicals and antioxidants. Blackcurrants can be eaten raw but are usually cooked in a variety of sweet or savoury dishes. They are used to make jams, jellies and syrups and are grown commercially for the juice market. The fruit is also used in the preparation of alcoholic beverages and both fruit and foliage have uses in traditional medicine and the preparation of dyes. As a crop, the blackcurrant suffers from several pests and diseases. The most serious disease is reversion, caused by a virus transmitted by the blackcurrant gall mite. Another is white pine blister rust which alternates between two unrelated hosts, one in the Ribes genus (blackcurrant included) and the other a White pine. This fungus caused damage to forests when the fruit was first introduced into North America, where the native white pines have no genetic resistance to the disease. As a result, the blackcurrant has for most of the 20th century been subject to restrictions in parts of the United States as a disease vector. The effectiveness of these restrictions is questionable, since other Ribes species also host the disease and are native to North America. Breeding is being undertaken in Europe and New Zealand to produce fruit with better eating qualities and bushes with greater hardiness and disease resistance. ==Description== ''Ribes nigrum'', the blackcurrant, is a medium-sized shrub, growing to by . The leaves are alternate, simple, broad and long with five palmate lobes and a serrated margin. All parts of the plant are strongly aromatic. The flowers are produced in racemes known as "strigs" up to long containing ten to twenty flowers, each about in diameter. Each flower has a hairy calyx with yellow glands, the five lobes of which are longer than the inconspicuous petals. There are five stamens surrounding the stigma and style and two fused carpels.〔(【引用サイトリンク】title=Black currant: ''Ribes nigrum'' )〕 The flowers open in succession from the base of the strig and are mostly insect pollinated, but some pollen is distributed by the wind. A pollen grain landing on a stigma will germinate and send a slender pollen tube down the style to the ovule. In warm weather this takes about 48 hours but in cold weather it may take a week, and by that time, the ovule may have passed the stage where it is receptive. If fewer than about 35 ovules are fertilised, the fruit may not be able to develop and will fall prematurely. Frost can damage both unopened and open flowers when the temperature falls below -1.9 °C (28.5 °F). The flowers at the base of the strig are more protected by the foliage and are less likely to be damaged. In midsummer the green fruit ripens to an edible berry up to 1 cm in diameter, very dark purple in colour, almost black, with a glossy skin and a persistent calyx at the apex, and containing several seeds dense in nutrients (notably Vitamin C). An established bush can produce about 4.5 kilograms (10 pounds) of fruit each year.〔 Plants from Northern Asia are sometimes distinguished as a separate variety, ''Ribes nigrum'' var. ''sibiricum'', of which ''Ribes cyathiforme'' is considered a synonym. 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「blackcurrant」の詳細全文を読む スポンサード リンク
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