A comparative study of polychlorinated biphenyl (PCB) metabolism by different plant species in vitro.

摘要

Polychlorinated biphenyls (PCBs) have wide industrial usage as dielectric fluids, refrigerants, and plasticizers. The environmental persistence of PCB's and their demonstrated toxicity to animals and humans have made this class of compounds a focal point of environmental concern around the world. Although no longer manufactured in this country, their prior use and disposal have resulted in their accumulation in sediments of streams, rivers, and the food chain. This study was done to determine the capacity of plants from diverse taxonomic groups and habitats to degrade non-recalcitrant and recalcitrant PCBs in vitro. During these phytoremediation experiments, cell lines from four dicots, Nicotiana tabacum, Simmondsia chinensis, Daucus carota, Ailanthus altissima; one monocot, Vetiveria zizanioides; one gymnosperm, Gingko biloba; and the leaf fragments from one monocot, Typha angustifolia; and one fern Nephrolepis exaltata, were tested. The cells were grown in continuous axenic culture at 25C under 12 hr LD photoperiods. Both the callus cell and the leaf fragments were grown separately in liquid culture containing a six congener PCB mixture. Analysis of the extracts from the plants and their media by a gas chromatograph containing an electron capture detector, indicated that all the plants used in this study possess varying capacities to aerobically degrade PCB's of low and high chlorine content. Among the plants tested, the amount of the PCB mixture metabolized was as high as sixty percent.