Miscanthus Andersson (PROSEA)
- Protologue: Öfvers. Förh. Kongl. Svenska Vetensk.-Akad. 12: 165 (1856).
- Family: Gramineae
- Chromosome number: x= 19;M. floridulus,'M. sinensis: 2n= 38;Miscanthuspossibly originated as an amphidiploid between species withx= 9 andx= 10
Major species and synonyms
- Miscanthus floridulus (Labill.) Warb. ex K. Schum. & Lauterb., Fl. Deut. Schutzgeb. Südsee: 166 (1901),synonyms: Saccharum floridulum Labill. (1824), Miscanthus japonicus Andersson (1856), M. formosanus A. Camus (1924).
- Miscanthus sinensis Andersson, Öfvers. Förh. Kongl. Svenska Vetensk.-Akad. 12: 166 (1856), synonyms: Saccharum japonicum Thunb. (1794, p.p.), Miscanthus purpurascens Andersson (1856), M. matsudae Honda (1923).
- General: miscanthus, silvergrass (En)
- Philippines: bilau (Igorot, Ifugao).
- M. floridulus : floret silvergrass (En)
- Indonesia: glagah (Javanese, Balinese)], toi (Halmahera), lolo (Ternate, Tidore)
- Philippines: bublung (Bontoc), buyao (Ifugao)
- Vietnam: cỏ chè vè.
- M. sinensis : eulalia (En)
- Indonesia: walana 'in cuntung (Minahasa)
- Philippines: rono (Ilokano), bigao (Bikol)
- Vietnam: chè vè trung hoa.
Origin and geographic distribution
Miscanthus originates from Asia and contains about 20 species, occurring in the Old World tropics, South Africa and East Asia. M. floridulus is distributed from East Asia through South-East Asia to Polynesia. M. sinensis is a more temperate zone species, native to China, Korea, Taiwan, Japan and eastern Russia, and introduced and established in Australia and North America. The extent of its distribution in South-East Asia is uncertain, but it seems to occur in the Philippines and Indo-China. Information on M. sinensis in Indonesia probably refers to M. floridulus . Both M . floridulus and M. sinensis are sometimes considered weeds.
The stems of M. floridulus and M. sinensis are suitable for thatching and widely used for this purpose, for instance in Indo-China, eastern Malaysia, the Moluccas, the Philippines, New Guinea, and the Pacific. They serve for making house walls in the Philippines and New Guinea. In the Philippines the stems are also made into fences, floor-coverings, coarse baskets, children's toys, novelty and souvenir items, supports for climbing vegetables or beans and drying racks for tobacco. In Luzon split stems serve for making screens and window shades. In the Moluccas and Papua New Guinea the stems are made into arrow shafts. Both M. floridulus and M. sinensis can be used for paper making.
Miscanthus shoots are eaten as a vegetable in East Kalimantan. The leaves are fodder for water buffaloes in the Philippines. The stems serve as fuel in the Philippines and Indo-China. Medicinal uses include the application of the juice or a decoction of Miscanthus on bites from wild animals in Indo-China, whereas in the Philippines a shoot decoction is taken against cough. In the Philippines Miscanthus stems with leaves are sometimes arranged in front of houses or other property as a sign not to enter or disturb.
Outside South-East Asia M. sinensis is widely planted as an ornamental, and also in hedges and windbreaks. In Japan it is cultivated as a forage plant and it has been used as a source of a yellow dye. M. floridulus is grown as an ornamental. In Taiwan it is planted as a shelter. Because of its high productivity, Miscanthus is being investigated in Europe as a renewable source of energy and a potential source of fibre for composite materials like MDF (medium density fibreboard) and chipboard, pulp for paper and packaging, biodegradable geotextiles (e.g. for temporary protection of slopes and banks), filters and sorbents, and insulation. Most research has focused on M. × giganteus Greef & Deuter ex Hodkinson & Renvoize, which is probably an allotriploid hybrid of M. sinensis and M. sacchariflorus (Maxim.) Hack., originating from East Asia and introduced into Europe in the 1930s.
Production and international trade
M. floridulus and M. sinensis are used locally in South-East Asia. No production or trade statistics are available.
The ultimate fibres of Miscanthus have an average length of 1.4-1.8 mm, a lumen width of 7 μm and a cell wall thickness of 6 μm. Miscanthus straw contains 38-48% α-cellulose, 26-34% hemicelluloses, 18-24% lignin and 2-6% ash. The α-cellulose and lignin levels of 2-year-old plants decrease from the base to the top of the stem, whereas the opposite occurs for hemicelluloses and ash. The lignin content of the leaves is lower than that of the stem tops, and the ash content higher, whereas the levels of α-cellulose and hemicelluloses in the leaves are similar to those in the stem tops. When separated into a chip fraction (mainly consisting of splintered internodes) and meal fraction (mainly ground leaves, nodes and husks), the chip fraction did not give better pulp quality than unfractioned material. In a comparative study in the United Kingdom, chemical (soda-anthraquinone) Miscanthus pulps were superior in yield (46-52%), tensile strength and tear strength to those of wheat straw, but inferior in brightness. Yields and tensile strength were similar to those of chemical (kraft) Eucalyptus pulp, but the tear strength and brightness were superior. Semi-chemical (neutral sulphite semi-chemical process) Miscanthus pulp did not compare favourably with semi-chemical hardwood pulp. Particle boards made of Miscanthus material were much inferior to those made of wood, but Miscanthus showed promise as raw material for MDF. Another study showed that good quality particle boards can be made of Miscanthus provided the glue used is PMDI (polymeric diphenylmethane-4,4-diisocyanate) instead of UF (urea formaldehyde), PF (phenol formaldehyde) or MUPF (melamine urea phenol formaldehyde).
Though the leaves of M. floridulus are sometimes used as fodder and appear excellent on chemical analysis, they are not very suitable because of their harshness. The scabrid-toothed leaf margins of M. floridulus can make severe cuts. The yellow colouring substance in M. sinensis is probably tricin. The glycoprotein fraction of a water extract of M. sinensis spikelets inhibited cutaneous allergic reactions in experiments with mice, and may be useful in the development of anti-allergenic therapies. The energy content of Miscanthus is about 16-19 MJ/kg dry matter.
Adulterations and substitutes
Numerous other plant species are used for thatching in South-East Asia, such as Imperata conferta (J.S. Presl) Ohwi and I. cylindrica (L.) Raeuschel. As a source of pulping material, Miscanthus mainly competes with hardwoods.
Robust, tufted, rhizomatous, perennial grasses with erect, solid culms. Leaves expanded, sheathed, ligule membranous, ciliate, blade linear, flat. Inflorescence usually an open, large, plumose panicle with tough rachis, repeatedly branched on all sides into numerous racemes; spikelets in pairs, small, equal, lanceolate, unequally pedicellate, falling entire, 1flowered, awned, with a spreading bundle of long silvery-white or coloured hairs at base; glumes equal, thin, 1-5nerved; lemmas smaller, upper lemma with central nerve excurrent into long or short awn; palea nerveless; lower floret reduced to a sterile hyaline lemma, upper floret bisexual; lodicules 2, cuneate; stamens 2-3; styles 2, free; stigmas 2, plumose. Fruit a subcylindrical caryopsis.
- M. floridulus . A robust, tufted, erect, perennial grass, 1.5-3 m tall. Culm terete, filled with pith, glabrous, pruinose below the nodes. Leaf-sheath glabrous or outer margin with long hairs; ligule 1-2 mm tall; blade 60-150 cm × 1-4.5 cm, base attenuate, margins very rough, apex acute, long hairy above the base or only just behind the ligule, otherwise glabrous and smooth with wide midrib. Inflorescence 30-45 cm long; branches numerous, erect or nodding, lower ones 20-40 cm long, solitary or 2-6 together, often from near base already with 3-10 long, lateral branches; spikelets not crowded; pedicels slender, thickened upwards, those of a pair 2-4 mm and 4-9 mm long respectively, both, or at least the longer one, ultimately rather divergent or recurved; spikelet about 4 mm long; basal hairs 5-11 mm long, white or purple; lower glume 3-5-nerved, upper glume 3-nerved; lower lemma 2.2-4.2 mm long, finely ciliate in upper half, 0-1-nerved; upper lemma 2-3.5 mm long, 3-nerved, awn twisted, 6-11 mm long; palea 1.5-2.7 mm long; stamens 3; stigmas exserted near middle of spikelet.
- M. sinensis. A robust, tufted, erect, perennial grass, 1.5-2.5 m tall. Leaves radical and cauline; blade 50-80 cm × 0.2-2 cm, stiff, very scabrous on the margin, pale or slightly glaucous beneath, midrib thickened toward base. Inflorescence a corymbose panicle, 20-30 cm long, main axis shorter than the 7-many raceme-branches; racemes 15-30 cm long; spikelets as in M. floridulus but longer, 5-7 mm long, tuft of hairs 7-12 mm long, awn 8-15 mm long.
Growth and development
Miscanthus spp. are perennial grasses. The estimated productive life of M. × giganteus is 10-20 years, but yields seem to decline after 10 years. Miscanthus follows the C4-cycle photosynthetic pathway, thus using CO2and water more efficiently than C3plants and having higher potential biomass yields. Daily growth rates up to 3-4 cm have been recorded. Unlike other C4-plants, e.g. maize ( Zea mays L.), Miscanthus retains its high photosynthetic capacity at temperatures below 14°C. Miscanthus is wind-pollinated and in Java M. floridulus flowers throughout the year. Miscanthus roots extend to a depth of 1 m or deeper.
Other botanical information
Literature on Miscanthus is often unreliable at the species level because the taxonomy of Miscanthus is not clear and is in need of revision. M. sinensis , for instance, has sometimes been grouped under M. floridulus . However, based on isozyme analysis it has been postulated that M. floridulus evolved from the more primitive M. sinensis . Hybridization between the now approximately 20 recognized Miscanthus species is common and has given rise to a large number of hybrids, many of which are sterile. Miscanthus is closely related to Saccharum L. with which it is able to hybridize. A specimen in the Linnean Herbarium annotated as Saccharum officinarum L. later appeared to be M. floridulus .
The soft-leaved M. sinensis var. condensatus (Hack.) Makino (synonym: M. condensatus Hack., by some considered as a separate species) occurs on seashores and sometimes on mountains in Japan; it is often cultivated as a fodder plant in the Ryukyu and the Idzu Islands. It also occurs in Korea, China, Indo-China and the Pacific. M . × giganteus is a hardy perennial 2.5-3.5 m tall; leaves flat and linear, usually more than 50 cm × 3 cm, ligule truncate with hairs; inflorescence 30 cm long with 15 cm long rachis; spikelets 4-6 mm long with tuft of hairs about 2 times longer; lower glume 5-6 mm long, upper glume 4-5 mm; sterile and fertile lemmas 3.5 mm long, not awned. Numerous, mainly ornamental Miscanthus cultivars are known, particularly of M. sinensis ; they differ in size and colour of foliage and inflorescence. Some well-known M. sinensis cultivars are "Goliath", "Purpureus", "Sarabande" and "Zebrinus".
Other Miscanthus species recorded from South-East Asia are M. nepalensis (Trin.) Hack., occurring in Malaysia (Pahang), India and Burma (Myanmar) and M. depauperatus Merr., found in the Philippines. No information is available on their uses. M. sacchariflorus (Maxim.) Hack. (synonym: Imperata sacchariflora Maxim.) is an important source of pulp for paper making in China and is under investigation as a biomass crop.
M. floridulus occurs in South-East Asia almost from sea-level up to 3000 m altitude, but mostly at 1000-2000 m. It is frequently found on rocky mountain slopes, in swampy locations and in waste or disturbed land. It also forms gregarious clumps and thickets in open sites in oak and secondary forest, tree-fern and bog grasslands. In Java M. floridulus is locally abundant in sunny or partly shaded, humid or sometimes marshy places, in forest edges, young forest, scrub vegetation and grass jungles, at 1350-2100 m altitude. M. floridulus is aggressive and can form dense communities. It survives fire through quick regeneration from subterranean parts. M. floridulus withstands wind and can grow in coastal areas where salt spray occurs. M. sinensis occurs at medium and higher altitudes in the Philippines. After repeated fires it may dominate areas completely.
Propagation and planting
Miscanthus is usually propagated vegetatively by division or rhizome cuttings. Rhizome cuttings for field planting are usually 8-15 cm long and can be stored between -1°C and 1°C. Not much success has been obtained with stem cuttings. M. floridulus and M. sinensis can be propagated by seed, though seed production has been difficult for M. floridulus in China and for some M. sinensis cultivars. The germination rate of M. floridulus increases with temperature between 15°C and 35°C, but the germination percentage is not affected by temperature in this range. The optimum temperature range for germination of M. sinensis seed is 20-30°C. In vitro micropropagation of various M. sinensis cultivars is possible with immature inflorescences on modified Murashige and Skoog (MS) medium with 9.0 μmol 2,4-D (2,4-dichlorophenoxyacetic acid) and 20 g/l sucrose, with organogenesis occurring 8-12 weeks after callus formation. Shoots can be rooted on half-strength MS medium and tillers will form, which can be separated for new rooting and tillering. Another micropropagation system for M. sinensis has been developed in which meristem tissue is removed from selected plants and cultured.
In Europe the practically sterile hybrid M. × giganteus is propagated vegetatively by rhizome cuttings or in vitro micropropagation and planted at a density of 5 000-40 000 plants per ha.
In South-East Asia Miscanthus is not planted but collected from the wild. Cultivated M. × giganteus in Europe needs to be weeded in the establishment phase (the first 2 years), but later on the crop is competitive enough to overcome weeds. Because of the high productivity, and in spite of the high water-use efficiency, the water requirement is high and irrigation is beneficial under southern European conditions. The response to fertilizer application varies with soil type, but in general the nutrient removal at harvesting is relatively low: 5-8 kg N, 0.5-1.5 kg P and 6-9 kg K per t harvested dry matter.
Diseases and pests
Miscanthus is attacked by rusts ( Puccinia spp.), a wide-ranging species being Puccinia miscanthae , and smuts ( Sphacelotheca spp. and Ustilago spp.). In Europe it is attacked by the Miscanthus streak virus. No information is available on diseases and pests affecting Miscanthus in South-East Asia.
In Europe M. × giganteus is harvested annually after nutrients have relocated to the rhizomes and the plants have dried to a dry matter content of at least 60%, and before new shoots occur. In northern Europe this is preferably in February or March, and in southern Europe in November. If it is harvested early, the biomass loss is low, but the moisture content is high. If it is harvested late, the moisture content is low, but biomass loss of up to 20% may occur. For the production of handicrafts in the Philippines, young stems are preferred.
Miscanthus yields in South-East Asia are unknown, but for China possible dry matter yields of up to 40 t/ha have been recorded. In Europe Miscanthus yields from the third year onwards normally range from less than 10 t/ha dry matter per year in northern Europe to about 25 t/ha dry matter per year in southern Europe under irrigated conditions. Experimental yields up to 41 t/ha dry matter have been recorded.
Handling after harvest
The stem is the most important part of Miscanthus as a source of fibre, and after harvest the stems must be separated from the leaves. In Indonesia the traditional way of preparing Miscanthus stems is to separate them and dry them in the sun. Young stems or shoots to be used for medicinal purposes are not dried.
M. floridulus and M. sinensis have a wide distribution and do not seem to be threatened with extinction. Some 14 accessions of M. floridulus are held at the Institute of Plant Breeding of the College of Agriculture UPLB in Laguna, the Philippines. Accessions of M. sinensis are held in Japan (Kumamoto Station National Livestock Breeding Centre, Kumamoto) and the United Kingdom (Institute of Grassland and Environmental Research, Aberystwyth).
In Europe some Miscanthus breeding work has been started, for instance on hybridization and polyploidization. Furthermore, M. sinensis and M. × giganteus genotypes are evaluated with respect to biomass yield, responses to low temperatures and frost tolerance. Miscanthus species are used in breeding programmes of sugar cane ( Saccharum officinarum L.), e.g. for bringing in disease resistance.
In South-East Asia Miscanthus will remain an important source of thatch. In the Philippines it is considered to have bright prospects as a material for handicrafts. Worldwide, it has potential as a non-wood source of fibre for composites such as MDF and pulp for paper making and packaging. Because of its high productivity, Miscanthus is a promising renewable source of energy.
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A.T. Karyawati & D. Darmakusuma