Giant reed (Arundo Donax L.): A green technology for clean environment

Abstract

In recent years, biomass plants have gained considerable public attention and interesting of environmental policy makers as important renewable source for energy. In addition, exploitation of biomass plants as promising phytoremediation candidates was proposed since these plants can produce huge biomass production under low-cost conditions as well as its ability to survive in contaminated and poor soils (marginal lands). Giant reed (Arundo donax L.) has been recognized as one of the most important energy plants as a consequence of its huge dry biomass production that can reach more than 60 t ha-1 under optimal growth conditions. Nowadays, giant reed becomes promising tool for phytoremediation purposes where it shows great ability to grow in different soils with wide ranges of pH, salinity and trace metal contents. Giant reed is a tall perennial rhizomatous grass (Poaceae family), native to the freshwater regions of Eastern Asia, but nowadays considered as a sub-cosmopolitan species given its worldwide distribution. It is a hydrophyte, growing along lakes, streams, drains and other wet sites. The genus Arundo can reach the height of 14 m and is among the fastest-growing terrestrial plants. Giant reed displays unique physiological features whereby it readily absorbs and concentrates toxic chemicals from contaminated soil with no appreciable harm to its growth and development. It is one of the mostly used plants as a trace element bio-accumulator, especially via phytoremediation processes, due to its capacity of absorbing contaminants such as metals that cannot be easily biodegraded. Many reports documented well that giant reed can efficiently decontaminate polluted soils with Cu, Cd, As, Pb Ni, high content of salts bauxite-derived red mud. Microbial component in soil is considered one of the most sensitive indicators for soil contamination especially with trace metals. Where, many microbial species significantly reduce directly after exposure to such pollutants except tolerant species. However, giant reed showed capability for healing and restoring the soil microbial community within phytoremediation process. Moreover, in autoclaved soil samples, giant reed was able not only to maintain soil chemical properties, but also to induce the microbial growth of different groups such bacteria, fungi and actinomycetes in a short period. These data encourages using giant reed for phytoremediation purposes as well as for recovering steaming soil as in natural fires. This chapter reviews the scientific literatures and presents innovative findings on the ability and utilization of giant reed biomass feedstock for phytoremediation and other uses.