SEDL / STP / STP1115-EB / STP19515S

Photoinduced Toxicity of Polycyclic Aromatic Hydrocarbons to the Higher Plant Lemna Gibba L. G-3

Huang, X-D
Visiting scientist, associate professor, and assistant professor, University of Waterloo, Waterloo, Ontario

Dixon, DG
Visiting scientist, associate professor, and assistant professor, University of Waterloo, Waterloo, Ontario

Greenberg, BM
Visiting scientist, associate professor, and assistant professor, University of Waterloo, Waterloo, Ontario

Pages: 8    Published: Jan 1991

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Abstract

Polycyclic aromatic hydrocarbons (PAHs) are known to exhibit photoinduced toxicity to animals and microorganisms, especially in the presence of ultraviolet (UV) irradiation. Since higher plants readily assimilate PAHs from the environment, and since they cannot avoid UV radiation (a natural component of solar radiation), PAHs have the potential to be a potent phytotoxicant. We have begun to assess the photoinduced toxicity of two PAHs (anthracene and phenanthrene) to the higher plant Lemna gibba. In the presence of low-intensity visible light (60 μmol m^-2 s^-1, 400 nm to 700 nm), anthracene and phenanthrene were found to be essentially nontoxic. However, both compounds were highly toxic to Lemna in low levels of simulated solar radiation [visible light, 30 μmol m^-2 s^-1; UV^A (320 nm to 400 nm), 4 μmol m^-2 s^-1; UV^B (280 nm to 320 nm), 0.6 μmol m^-2 s^-1]. Furthermore, in the absence of plant tissue, anthracene and phenanthrene were chemically modified by simulated solar radiation. These photomodified PAHs exhibited toxicity in visible light and increased toxicity in simulated solar radiation.