|
Ramie (, ) is a flowering plant in the nettle family Urticaceae, native to eastern Asia. It is a herbaceous perennial growing to 1–2.5 m tall;〔(Ramie: Old Fiber - New Image )〕 the leaves are heart-shaped, 7–15 cm long and 6–12 cm broad, and white on the underside with dense small hairs—this gives it a silvery appearance; unlike stinging nettles, the hairs do not sting. The true ramie or China grass, is also called Chinese plant or white ramie. A second type, known as green ramie or rhea, is believed to have originated in the Malay Peninsula. It has smaller leaves which are green on the underside, and it appears to be better suited to tropical conditions.〔 The word ''ramie'' is derived from the Malay word ''rami''.〔"ramie", entry, p. 156, vol. 13, ''The Oxford English Dictionary'', 2nd ed., Oxford: Oxford University Press, 1989, ISBN 0-19-861225-7.〕 ==Cultivation== Ramie is one of the oldest fiber crops, having been used for at least six thousand years, and is principally used for fabric production. It is a bast fiber, and the part used is the bark (phloem) of the vegetative stalks. Ramie is normally harvested two to three times a year but under good growing conditions can be harvested up to six times per year. Unlike other bast crops, ramie requires chemical processing to de-gum the fiber. Harvesting is done just before or soon after the beginning of flowering. It is done at this time because at this stage there is a decline in plant growth and the maximum fiber content is achieved.〔 Stems are harvested by either cutting just above the lateral roots or else bending the stem. This will enable the core to be broken and the cortex can be stripped from the plant in situ.〔 After harvesting, stems are decorticated while the plants are fresh. If this is not done while the plants are still fresh the plants will dry out and the bark will be hard to remove. The bark ribbon is then dried as quickly as possible. This will prevent bacteria and fungi from attacking it.〔 The dry weight of harvested stem from crops ranges from 3.4 to 4.5 t/ha/year, so a 4.5 ton crop yields 1,600 kg/ha/year of dry non-de-gummed fiber. The weight loss during de-gumming can be up to 25% giving a yield of de-gummed fiber of about 1,200 kg/ha/year.〔 The extraction of the fiber occurs in three stages. First the cortex or bark is removed; this can be done by hand or by machine. This process is called de-cortication. Second the cortex is scraped to remove most of the outer bark, the parenchyma in the bast layer and some of the gums and pectins. Finally the residual cortex material is washed, dried, and de-gummed to extract the spinnable fiber.〔 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「ramie」の詳細全文を読む スポンサード リンク
|