The presence of toxic amounts of boron (B) in soils, either from irrigation water or from industrial wastes, decreases crop yields in many regions of the world. Wastewaters, especially from electric utilities, may be contaminated with B and there are no cost-effective, efficient methods for its removal. Upland and wetland plants could provide an efficient means for extracting B from wastewater, respectively, through absorption and subsequent sequestration in above-ground tissues, which may then be removed. Several mesocosm systems with diferent types of water recirculation and a selection of plant species are being tested, including cattail, vetiver and poplar trees. Recent advances in plant biotechnology create a very real opportunity to enhance the capacity of individual plant species to take up and accumulate B. We envision that this can be achieved by elucidating the specific characteristics (physiological, biochemical and molecular) of plants and bacteria that have the capacity to either hyperaccumulate or exclude B from their cells. By identifying the genes responsible for B hyperaccumulation and/or exclusion, we should be able to develop transgenic plants for subsequent use as part of biological treatment systems for B cleanup.
Cattail plants (left) and Puccinellia distans (right) in diferent hydroponic systems for B removal from wastewater.
