Arundo donax (PROSEA)
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Introduction |
Arundo donax L.
- Protologue: Sp. pl.: 81 (1753); Gen. pl. ed. 5: 35 (1754).
- Family: Gramineae
- Chromosome number: 2n= 100, 110, 112
Synonyms
Arundo sativa Lamk (1779), Donax arundinaceus P. Beauv. (1812), Scolochloa donax (L.) Gaudin (1828).
Vernacular names
- Giant reed, Spanish reed, bamboo reed (En). Canne de Provence, grand roseau (Fr). Burma (Myanmar): alokyu
- Laos: khem
- Thailand: o (general), o luang (northern), o yai (central)
- Vietnam: sậy, lau.
Origin and geographic distribution
A. donax is distributed from the Mediterranean region to southern Asia. It has been cultivated in southern Europe and elsewhere since antiquity and has been introduced into many other parts of the world, including South-East Asia, Australia, southern Africa and America. It is widely naturalized in many countries and is sometimes considered a noxious weed, for instance in the United States.
Uses
Split young culms of A. donax are widely employed for weaving articles such as baskets, mats, trays, lattices and chair-seats, for instance in Europe and India. Unsplit culms are made into a number of items including fishing rods, umbrella-handles, walking-sticks and fish traps. They are also used for light construction work, fences and as supports for plants. The leaves have been employed for tying and for thatching. In Mexico A. donax is woven into various types of baskets, cradles and mats. A. donax can be utilized, alone or in combination with Eulaliopsis binata (Retz.) C.E. Hubbard, Phragmites vallatoria (Pluk. ex L.) J.F. Veldkamp, or bamboos, for the production of printing, writing and wrapping paper. It can also be used for fibreboard manufacture. In Italy it is a source of cellulose for rayon production.
A. donax canes have long been made into musical instruments, such as flutes and are still the main source of reeds for clarinets, oboes, bassoons, saxophones and bagpipes. It is cultivated for this purpose in south-eastern France and, to a small extent, the United States (Texas and California).
The young shoots of A. donax are sometimes eaten. It has little importance as forage, but is grazed by cattle when other fodder is scarce. A. donax is widely grown as an ornamental, for instance in Java. It is planted for erosion control, for instance for dune stabilization (e.g. in Pakistan and Tunisia) and in windbreaks. Because of its high biomass production A. donax is under investigation as a renewable and CO2-neutral source of energy in Europe and elsewhere. It is also being investigated as an element of plant-based systems for wastewater treatment.
The role of A. donax in South-East Asia is still limited. It has been introduced into Peninsular Malaysia, where it is occasionally cultivated as an ornamental (the variegated form) and for stabilization of embankments (the non-variegated form). In Indo-China tall stems are made into fishing rods and medicinally the rhizomes are considered to have lactifugal properties. In Burma (Myanmar) the root is used as a diuretic.
Production and international trade
In the late 1950s, the annual production of A. donax cane for the manufacture of reeds for musical instruments was estimated at 90-140 t in France and 10 t in the United States. An estimated 15-20 million reeds were produced in France and 5-7 million in the United States. No recent production or trade statistics for A. donax are available.
Properties
Mature culms of A. donax are hollow, with a diameter of 1-4 cm and walls 2-7 mm thick. Young culms have a diameter similar to that of mature ones, but their walls are thinner. The culms are divided by partitions at the nodes. The nodes form 10-25% of the stem mass, depending on the length of the internodes. The nodes and internodes contain 38% and 34% fibre, respectively. The outer stem tissue is very hard and brittle, with a smooth, glossy surface, which turns pale golden-yellow when the culm is mature. The collateral vascular bundles are freely distributed through the cross-sectional area of the parenchymatous inner ring, but those near the periphery are smaller and more numerous. The bundles in the interior are normally enclosed by a single row of fibres, but the number of rows of fibres increases towards the periphery, until they form a continuous ring of structural tissue with scattered vascular elements. A. donax culms are stronger than those of other Gramineae , but less strong than bamboo. For the production of articles such as baskets and lattices, young canes are preferred because they are more supple and thus more easily worked than older ones.
The ultimate fibre cells in A. donax culms are (0.1-)1.2-1.5(-5.4) mm long and (7-)15-17(-41) μm wide, with an average wall thickness of 5 μm. On average the ultimate fibre cells of the nodes are 1.2 mm long and 16.9 μm wide, with a cell wall thickness of 5.3 μm, whereas those of the internodes are 1.2 mm long and 14.6 μm wide, with a cell wall thickness of 4.6 μm. Information on the chemical composition of A. donax varies widely. Dry A. donax culms contain approximately 44-46% α-cellulose, 26-29% hemicelluloses, 22-24% lignin, 2-7% ash and 1-2% lignin. In Portuguese studies in the 1990s, however, lower cellulose contents were found: the nodes contained 28-34% α-cellulose, 22–32% hemicelluloses, 16-22% lignin and 3-5% ash; the internodes 32-36% α-cellulose, 21-30% hemicelluloses, 16-22% lignin and 4-6% ash. The lignin content of nodes and internodes decreased from the base (20-22%) to the top (16%) of the stem. The foliage contained about 35% α-cellulose, 26% hemicelluloses, 17% lignin and 6% ash.
The absence of pith in the stems, in contrast to e.g. Miscanthus Anderss., makes pulping easier. In experiments using the kraft (sulphate) and soda processes, unbleached pulp yields of about 35% have been obtained when air-dry culms with leaves were used, and 40-45% when culms without leaves were used, but the strength of both pulps was rather low (breaking length 6300-7000 m). Leaves alone give lower pulp yields and poorer strength. In France it has been recommended not to use the leaves for pulping because of their high silica content, but in India the use of culms with leaves for pulp production proved more economical. Large-scale tests in the United States led to the conclusion that A. donax is not a satisfactory source of pulp if strength is important, but it may serve for the production of special papers. Studies using kraft pulping have shown that the internodes are more suitable for pulping than the nodes, with the latter having an adverse effect on pulp yield and properties. Screened pulp yields of 42%, 45% and 39% were obtained for whole stems, internodes and nodes, respectively. Pulp of internodes had lower residual lignin contents and better strength properties, brightness and viscosity than that of nodes. The strength properties of whole stem pulps are similar to or lower than those from internodes. Beaten kraft pulps from A. donax showed paper making properties comparable to hardwood kraft pulps, and their properties can be improved by removing nodes from the crushed stems before pulping. Pulps with high yield and low residual lignin content, comparable with kraft pulps from hardwoods, have been produced from A. donax using various organosolv processes. The main disadvantages of kraft and organosolv pulps of A. donax , compared to wood pulps, are the fast response to beating and drainage problems.
The suitability of reeds from A. donax canes for woodwind instruments is due to their resilience, elasticity and resistance to moisture. They respond instantly to minute changes in pressure and do not crack or split easily.
Defatted ethanolic rhizome extracts of A. donax have shown hypotensive and antispasmodic action against histamine-, serotonin- and acetylcholine-induced spasms. The rhizome contains the alkaloids gramine (donaxine), bufotenine and bufotenidine. Gramine has shown weak parasympathomimetic action. Small doses raise blood pressure in dogs and cats, but larger doses lower it. The same effects were found with gramine hydrochloride in anaesthetized cats. The leaves and flowers also contain gramine. Crude whole plant extracts of Thai A. donax and several isolated compounds, including triacontanol and tricin, have shown antifeedant activity against the boll weevil Anthonomus grandis , an important cotton pest. The energy content of A. donax is about 15-17 MJ/kg dry matter.
Adulterations and substitutes
As a source of pulping material, A. donax mainly competes with hardwoods. Compared with hardwoods, it has some disadvantages, such as a relatively low fibre content (30-36%) and high parenchyma content (around 60%), and higher silica and ash content. The advantages include high biomass productivity, annual harvesting, and tolerance to a wide range of ecological conditions. It also has a lower lignin content, making simple pulping methods with reduced chemical charge possible.
As a source of reeds for musical instruments A. donax has no satisfactory natural substitutes, the exception being bagpipe reeds, which can be made of elder stems and goose quills as well. Synthetic reeds are available but are usually unacceptable to professional musicians.
Description
A robust, strongly tufted, rhizomatous, perennial grass up to 8 m tall. Rhizome often far creeping, fleshy to woody, forming compact masses from which tough fibrous roots arise that penetrate deeply into the soil. Culm terete, 2-8 m × 1-4 cm, with solid nodes and hollow internodes 12-30 cm long, erect or nodding, often copiously branched, pruinose below the nodes, outer tissue very hard and brittle with a smooth glossy surface that turns pale golden-yellow upon maturity. Leaves conspicuously distichous, sheathed; sheath at first ciliate along the margins and with long hairs at the mouth, afterwards glabrous; ligule a short scarious membrane; blade linear-lanceolate, 15-75 cm × 1-8 cm, base rounded or cordate, margins very rough, apex long-attenuate, on the lower surface with a few shallow depressions caused by the pressure of the mouths of older sheaths, in wild specimens subglaucous, in cultivated plants often with yellowish-white longitudinal stripes or the smaller blades often entirely pale yellow, glabrous and smooth. Inflorescence an open or contracted, repeatedly branched panicle, 30-75 cm long, with scabrid axis and fascicled branches, silkily hairy but glabrous at the bases of the lowest branches; spikelets 3-4-flowered, 10-15 mm long, yellowish-green or tinged with purple; glumes subequal, lanceolate, 8-13 mm long, the lower a little shorter than the upper; lemma lanceolate, 6-13 mm long, 3-5-veined, 3 of the veins produced as short awns, hairy all over the back below the middle with hairs up to 8 mm long; palea 5-6 mm long, with 2 densely ciliate keels; stamens 3; pistil with glabrous ovary, 2 free, short styles and 2 plumose stigmas. Fruit (often not produced) a cylindrical caryopsis.
Growth and development
The growth of A. donax is rapid, with a height increase of up to 7 cm per day under favourable conditions. In southern France the culms normally branch during the 2nd year of growth and die the following winter, but some culms may survive and branch further in the 3rd growing season. During each growing season new culms arise from the rhizomes, giving the crop a perennial character. In Java (Indonesia) A. donax flowers in February and March, but in Bogor it has never been found flowering. It rarely produces viable seed, but plants have been grown from collected seed in western Asia. Under natural conditions A. donax usually spreads through rhizome growth. In natural stands near Jaipur (India) the standing aboveground dry biomass was 3.6-5.7 kg/m2, and the belowground biomass 4.8-5.2 kg/m2.
Other botanical information
Opinions about the number of species in Arundo L. vary from 1 to 12, but the most commonly accepted number is 3, occurring in tropical and temperate regions.
Though A. donax is rather uniform, several ornamental forms have been distinguished, mainly differing in their variegated leaves. The best-known is A. donax "Variegata" (also known as A. donax "Versicolor" based on A. versicolor Miller), with white-striped leaves, usually with broad white bands at the margins. It may reach a height of 4-5 m, but is often not taller than 0.6-1 m, with culms up to 1.5 cm in diameter. Its growth is denser than that of typical A. donax due to greater culm and leaf production, and it is less hardy. It is occasionally cultivated in Peninsular Malaysia, where it is called "tebrau gading".
A. donax is often confused with Phragmites vallatoria (synonym: P. karka (Retz.) Steud.), from which it can be distinguished by its membraneous ligule and its generally broader leaves, which are cordate at the junction with the sheath.
Ecology
A. donax is a plant of warm-temperate and subtropical regions, but tolerates a wide range of ecological conditions. It grows in regions with a rainfall between 300-4000 mm and average annual temperatures of 9-29°C, and normally survives prolonged periods of severe drought or excessive rain. During the first year of growth, however, growth can be seriously retarded by drought. The ability to tolerate extreme drought is due to the presence of rhizomes and a deeply penetrating root system. A. donax can survive very low temperatures when dormant but is seriously damaged by frost after growth has started. Young culms have little wind resistance. A. donax grows on many soil types, from heavy clay to loose sand and gravelly soils, but prefers well-drained soils with ample moisture. Salt or brackish conditions affect growth negatively. It favours wet habitats, such as lake borders or along ditches and canals, but once established it will also grow in drier locations. It does not grow in swamps, as the rhizomes do not withstand prolonged submersion in water. In East Java A. donax grows wild at 1000-1800 m altitude.
The ecological requirements for the production of reeds for musical instruments are often considered to be more rigid: low relative humidity and deep light soils with sufficient but not too much moisture prevent highly vigorous growth which would result in soft, porous canes.
Propagation and planting
A. donax is normally propagated by rhizome division. It may also be propagated by stem cuttings placed horizontally in moist soil, with young plants developing on the nodes. Stem pieces as short as 2 cm may be used. In storage the viability of rhizome and stem parts decreases, but rhizomes and stems kept for 16 weeks under cool (9-10°C) and moist conditions (plastic bag with moist soil) still produced about 75% and 70% sprouting, respectively. Rhizome parts planted as deeply as 25 cm readily sprout, but sprouting of stem parts is hindered by planting deeper than 10 cm. Stem cuttings may be directly planted in the field or they may first be placed in plastic bags and transplanted later. In southern France rhizomes or rooted stem cuttings are placed at a depth of about 10 cm, in rows 2-3 m apart, to enable mechanized operations. Until the soil becomes covered with A. donax , the space between rows may be utilized for the cultivation of other crops. When A. donax is grown as an energy crop, spacings of 0.7 m between rows and 0.5 m within rows may be applied when rhizome cuttings are used. When stem cuttings are planted, the within-row spacing may be closer, because they are cheaper and initial growth is slower.
Husbandry
During the first year in southern France A. donax is irrigated when necessary and weeded once or twice. During early development, the canes are cut periodically to encourage spreading of the rhizomes and to increase the density of the stand. Established plantings effectively suppress weeds and receive little attention other than the periodic removal of large weeds and small or inferior canes. Removal of A. donax where it is a weed requires treatment with systemic herbicides. For the cultivation of A. donax as an energy crop in Europe it is recommended that phosphorus be incorporated in the soil before establishing a plantation.
Diseases and pests
Little is known about the effects of diseases and pests on the growth and reproduction of A. donax , though numerous insects are known to feed on it. A. donax is a host of the root-knot nematode Meloidogyne incognita .
Harvesting
A. donax to be used for paper making or energy production can be harvested yearly from 2 years after planting onwards. Mechanical harvest is possible with forage harvesters or machines devised for sugar-cane harvesting. The culms have to be transported to the processing factory immediately to prevent deterioration of pulping quality. Plantings require up to 5 years before producing the first full crop of good-quality cane for musical instruments; in established plantations the canes to be used for reeds are selectively cut during the winter months when they are 2-3 years old.
Yield
Estimates of average annual dry matter yields of A. donax vary from about 7 t/ha for wild stands in India up to 43 t/ha for Italian plantings. In southern France annual dry biomass yields of 20-25 t/ha are obtained, but potential production estimates are as high as 100 t/ha. About 15% of the dry matter produced consists of leaves. Normally, less than 5% of the total dry matter production is suitable for the production of reeds for musical instruments. No information exists on yields in South-East Asia.
Handling after harvest
A. donax material to be used for paper making has to be dried, preferably artificially, because fermentation may occur during the slow process of natural drying. A. donax for rayon pulp in Italy is harvested during the winter and dried in the open for several months. The dried material is collected, placed in piles, and seasoned for some months. After this, the culms are crushed and cut into pieces about 2 cm long, the leaves and sheaths are removed, and the chips are processed into pulp.
For mat-making in Mexico the canes are soaked in water and crushed with a rock before being woven. In the Toluca region of Mexico baskets are made with the warp elements (vertical strands) made from split stems of A. donax and the weft elements (the horizontally woven strands) from narrowly cut strips of the same material.
Textile fibre has been made from A. donax by splitting the culms into long strips, treating them with a caustic solution and separating fibres suitable for spinning by beating the material. The fibres obtained were about 35 cm long and could be processed like hemp.
Canes intended to be used for reeds for musical instruments are traditionally tied in large bundles, often with leaves and branches intact, stacked and dried for at least 2-4 months, in which period the leaf sheaths rot. After this, the upper branching portions of the canes and the remaining leaves and sheaths are removed, and the canes are cut into pieces about 1.2 m long. Spoiled or cracked canes are discarded and the remaining material is cured in the sun for at least 3 weeks. As soon as the exposed surface turns to a creamy colour, the canes are turned so that another surface is exposed to the sun. Cured canes are stored in sheds, where they may be retained for a further period of curing or immediately marketed. By the time properly seasoned cane is ready for use, which may be 3-5 years after harvesting, its colour has become a rich golden-yellow. The cane is divided into tubes by cutting about 1 cm on either side of the nodes. Tubes of inferior quality are discarded. Reeds are frequently made of canes harvested when only a few years old and dried artificially, probably resulting in a lower quality.
Genetic resources
As A. donax has a wide distribution, it does not seem liable to genetic erosion. No germplasm collections are known to exist.
Breeding
Breeding efforts in A. donax are hampered by the fact that it seldom produces seed. Therefore it is recommended that any breeding programme be preceded by a study into the possibilities of overcoming this sterility, which would result in broader genetic variability.
Prospects
Although A. donax occurs in South-East Asia, it is not much used there. There may be some prospect in promoting its use as weaving material and for thatching, because of its high productivity. Furthermore, A. donax is a promising raw material for the production of paper.
Literature
1 Arnoux, M., 1974. Recherches sur la canne de Provence (Arundo donax L.) en vue de sa production et de sa transformation en pâte à papier [Research on giant reed (Arundo donax L.) in view of its production and processing into paper pulp]. Annales de l'Amélioration des Plantes 24(4): 349-376. 2 Bhat, R.V. & Virmani, K.C., 1951. Indigenous cellulosic raw materials for the production of pulp, paper and board. Part I. Pulps for writing and printing papers from Arundo donax L. Indian Forest Leaflet No 123. 9 pp. 3 Boose, A.B. & Holt, J.S., 1999. Environmental effects on asexual reproduction in Arundo donax. Weed Research 39(2): 117-127. 4 Dalianis, C.D., 1998. Giant reed (Arundo donax L.). In: el Bassam, N. : Energy plant species: their use and impact on environment and development. James & James (Science Publishers) Ltd., London, United Kingdom. pp. 150-155.
- Egré, D., 1976. La canne de Provence deviendra-t-elle une source d'approvisionnement de la papeterie Française? [Giant reed, will it become a source of supply for the French paper industry?]. Revue Forestière Française 28(2): 138-147.
- Ghosal, S., Dutta, S.K., Sanyal, A.K. & Bhattacharya, S.K., 1969. Arundo donax L. (Gramineae). Phytochemical and pharmacological evaluation. Journal of Medicinal Chemistry 12(3): 480-483.
- Pascoal Neto, C., Seca, A., Nunes, A.M., Coimbra, M.A., Domingues, F., Evtuguin, D., Silvestre, A. & Cavaleiro, J.A.S., 1997. Variations in chemical composition and structure of macromolecular compounds in different morphological regions and maturity stages of Arundo donax. Industrial Crops and Products 6: 51-58. 8 Perdue, R.E., 1958. Arundo donax - source of musical reeds and industrial cellulose. Economic Botany 12(4): 368-404. 9 Shatalov, A.A. & Pereira, H., 2002. Influence of stem morphology on pulp and paper properties of Arundo donax L. reed. Industrial Crops and Products 15(1): 77-83. 10 Shatalov, A.A., Quilho, T. & Pereira, H., 2001. Arundo donax L. reed - new perspectives for pulping and bleaching: 1. Raw material characterization. Tappi Journal 84(1): 96.
Authors
D. Darmakusuma & A.T. Karyawati
