| Popis: |
Boron is essential for plant growth but it is also toxic at higher concentrations. Excessive boron concentrations in soils and water are common problems in arid and semiarid regions. This strongly limits agricultural activities by reducing crop yields and the variety of species that can be cultivated. Current technologies for treating boron-polluted soils (e.g., leaching, adding lime, and soil replacement) are either expensive or impractical for these regions, hence new alternatives are required. Phytoremediation has gained much attention because it is a potential environmentally friendly and low-cost solution for cleaning contaminated sites. During the last two decades, three phytoremediation strategies for boron-polluted sites have been investigated: phytoextraction, phytorestoration, and phytomanagement. The aim of this chapter is to review the current knowledge about these three phytoremediation strategies. This chapter presents: (a) the background of the boron toxicity problem, (b) the studies done up to date in boron phytoextraction, with a discussion of the main factors that influence boron uptake by plants and strategies to enhance it, (c) the phytomanagement of boron-contaminated sites using poplars, and (d) the potential of a Gramineae species to restore soil properties in a boron-contaminated mine. Based on the available literature, we conclude that phytoremediation of boron-contaminated sites is a promising alternative to conventional treatments. Nevertheless, there are still several issues that need to be addressed. New investigations, such as studying the potential of genetically modified plants for phytoextraction, could help in bringing boron phytoremediation to widespread application. |
