Plant 189

Arundo donax L. (Poaceae)


Giant reed

Since ancient times, the term 'reed' has been applied to many different plant species, most of which are tall, grass like and grow near water. One of the most imposing of these species is the giant reed, a multi-purpose grass that has been used for millennia in western Asia and the Mediterranean. The vertical stems of the giant reed stems can reach ten metres tall and three centimetres in diameter, and have been used for thousands of years as fundamental construction materials for building houses, thatching roofs and making baskets, furniture and musical instruments.

The vertical stem of the reed is a hollow cylinder divided at intervals by horizontal walls, and is constructed of three concentric tissue rings: a hard, waxy epidermis, a band of thick-walled fibres and a thick inner layer of vascular bundles.

Reed stems include high proportions of cellulose, a material that has been industrially significant since the eighteenth century, for example, in the production of low-quality paper. In Italy during the 1930s and 1940s, the importance of giant cane cellulose became nationally important. It was the raw material needed for the production of the synthetic fibres rayon and viscose.

Interest in reed cellulose has been revived in the twenty-first century as people have become concerned with carbon emissions, and the search for biofuels to replace or supplement our use of fossil fuels has increased. Cellulose-rich reeds have been suggested as biomass crops for energy production. However, the high silica content of reeds mean clinker build-up can be a problem in furnaces, when they are burned. Consequently, the use of chemicals and enzymes that will efficiently convert cellulose in reed cell walls into liquid fuels is being explored.

One of the most famous uses of the giant reed stem is to make musical instruments. Cutting reed stem into different lengths creates a simple musical instrument: panpipes. More significantly, fine stems may be fashioned into reeds for woodwind instruments, such as the clarinet, bassoon and oboe. The layered structure of the reed's vertical stem is essential in determining the quality of instrument reeds.

In addition to vertical stems, giant reeds have horizontal, underground stems (rhizomes). Rhizomes grow rapidly and have roots that bind soil particles and limit soil movement. Consequently, reeds are important for stabilizing the banks of watercourses, modifying patterns of water flow and even acting as flood defences. Furthermore, they can aerate and clean polluted water.

Further reading

Kolesik P et al. 1998. Anatomical characteristics affecting the musical performance of clarinet reeds made from Arundo donax L. (Gramineae). Annals of Botany 81: 151-155.

Mariani C et al. 2010. Origin, diffusion and reproduction of the giant reed (Arundo donax L.): a promising weedy energy crop. Annals of Applied Biology 157: 191-202.

Naik SN et al. 2010. Production of first and second generation biofuels: A comprehensive review. Renewable and Sustainable Energy Reviews 14: 578-597.

Stephen Harris