The Toxic Effects Of Polycyclic Aromatic Hydrocarbons (Anthracene, Phenanthrene, Fluorene)on Young Sporophytes Of Undaria Pinnatifida

The influence of polycyclic aromatic hydrocarbons（PAHs） on young sporophyte ofUndaria pinnatifida was studied through the research of toxic effect of anthracene,phenanthrene and fluorene of different concentration on young sporophyte under thecondition of acute toxicity test（96h） and chronic toxicity test（30d）. The cell physiologicalchanges in sea weeds caused by PAHs and its ecological response mechanism werepreliminarily discussed in this paper.The Undaria pinnatifida seeds were collected in June and then cultivated till September,when most of the young sporophytes reached the length of70μm.Median lethal concentration was obtained by acute toxicity test of anthracene,phenanthrene and fluorene on Undaria pinnatifida sporophytes. The results showed that allthe three polycyclic aromatic hydrocarbons resulted in the rupture of cell wall, exudation ofcellular content and chloroplast death such as disorderion. The median lethal concentration ofanthracene, phenanthrene and fluorine on the Undaria pinnatifida young sporophyte of96hwas533.32μg/L,422.89μg/L and381.42μg/L, respectively. And the toxic effect was fluorene＞phenanthrene＞anthracene.According to the results of acute toxicity test of96h LC₅₀, the concentration of PAHs inthe following tests was set as1μg/L,10μg/L,50μg/L,100μg/L and250μg/L.Results of acute toxicity test showed that:1. Content of chlorophyll a decreased underhigh concentration（＞50μg/L）, while increased under low concentration（≤10μg/L）;2. SODactivity, CAT activity and POD activity under anthracene decreased after an increase. All ofMDA activity, CAT activity under phenanthrene and fluorine and the carotenoid contentunder high concentration（50-250μg/L） increased, while the carotenoid content decreasedunder low concentration（1μg/L and10μg/L）.Results of chronic toxicity test（30d） were as follows:1. Chlorophyll a content decreasedas the concentration of anthracene, phenanthrene and fluorine increased. Chlorophyll aincreased with the extension of time under low concentration（≤10μg/L）, while decreasedunder high concentration（＞10μg/L）;2. Activity of SOD, CAT and POD all increased firstand then decreased, and decreased as the concentration increased. Activity of SOD, CAT andPOD all increased during0-5d, while decreased gradually after5d or10d. MDA activity increased with the extension of time and the increase of concentration, and leveled offeventually. Carotenoid content increased as the concentration increased, while decreased withthe extension of time under low concentration（1μg/L and10μg/L）;3. DNA damage ofUndaria pinnatifida young sporophytes become more and more serious as time andconcentration increased.