Kuhn Achim, Ballach Hans-Joachim, Wittig Rüdiger
Dept. of Ecology and Geobotany, Botanical Institute, Johann Wolfgang Goethe-University, Siesmayerstrasse 70, D-60323 Frankfurt/Main, Germany.
Environ Sci Pollut Res Int. 2004;11(1):22-32. doi: 10.1065/espr2003.11.178.
Cuttings of Populus nigra L. cv. Loenen were cultivated in sand treated with one of the following PAHs: phenanthrene (Phen), fluoranthene (Flt), pyrene (Pyr), chrysene (Chr) and benzo[a]pyrene (BaP). The PAHs were applied at varying levels of concentration to each test series. After 6 weeks the concentration and the distribution of the PAHs in the substrate of the various sets of tests were compared with the concentration in the substrate of the control. Additionally the substrate and the plant roots were tested for evidence of degradation products of PAHs. The results revealed that the levels of concentration of Phen and Pyr detected in the substrate surrounding the roots was in some cases significantly lower than in the corresponding section of substrate in the unplanted set (= control). This phenomenon did not occur for Flt and BaP and in the case of Chr only in those substrates, which had been treated with the highest levels of concentration. As the presence of lesser amounts of Phen and Pyr in the plant pots cannot only be attributed to their accumulation and metabolism in the roots, it is fair to assume that the chemical transformation of these three PAHs took place outside the roots. The set of tests treated with Phen revealed the presence of 2- or 3-hydroxy-Phen (main components), a hydroxy-methoxy-Phen, 9,10-Phenanthrenequinone and one unidentified compound in metabolite form. Altogether eleven metabolites of Pyr were identified in the root extracts, which can be divided into three groups: 1-Hydroxy-Pyr and derivatives, dihydroxy-Pyr and derivatives and ring fission products (4-Hydroxy-Pyr and a derivative of the 4-Phen-carbonic acid). However, the metabolite mass detected for Phen and Pyr represents only an insignificant percentage in comparison with the lesser amounts of PAHs observed in the planted set of tests. This indicates that the three PAHs were reduced to lower molecular compounds, which are methodically impossible to record, and subsequently translocated to other parts of the plant and integrated into the biomass. Although no lesser amount for Flt and BaP was found in the plant pots, 1-Hydroxy-Flt, an unidentified compound of Flt and 1-Methoxy-BaP were detected. These are presumably end products which were enhanced in the roots. It was not possible to identify any transformation products of Chr. It can be assumed that the majority of metabolites were not synthesised in the roots but are a result of microbial degradation in the rhizosphere. The test plants improved the conditions for the biotransformation of Phen and Pyr significantly and accumulated Flt, Pyr, Chr and BaP in their roots. It can therefore be concluded that the use of plants in the bioremediation of contaminated soils is a promising option.
黑杨派无性系“洛嫩”的插条在经过下列多环芳烃之一处理的沙子中培养：菲（Phen）、荧蒽（Flt）、芘（Pyr）、 Chrysene（Chr）和苯并[a]芘（BaP）。将多环芳烃以不同浓度水平应用于每个测试系列。6周后，将各个测试组基质中多环芳烃的浓度和分布与对照组基质中的浓度进行比较。此外，还对基质和植物根系进行了测试，以寻找多环芳烃降解产物的证据。结果表明，在根周围基质中检测到的菲和芘的浓度在某些情况下明显低于未种植组（=对照组）基质的相应部分。荧蒽和苯并[a]芘未出现这种现象，对于 Chrysene，仅在那些用最高浓度处理的基质中出现这种现象。由于花盆中菲和芘含量减少不能仅归因于它们在根中的积累和代谢，因此可以合理推测这三种多环芳烃的化学转化发生在根外。用菲处理的测试组在代谢物形式中显示出2-或3-羟基菲（主要成分）、一种羟基甲氧基菲、9,10-菲醌和一种未鉴定的化合物。在根提取物中总共鉴定出芘的11种代谢物，可分为三组：1-羟基芘及其衍生物、二羟基芘及其衍生物和环裂解产物（4-羟基芘和4-苯碳酸的一种衍生物）。然而，与种植测试组中观察到的较少多环芳烃量相比，检测到的菲和芘的代谢物质量仅占微不足道的百分比。这表明这三种多环芳烃被还原为分子较小的化合物，按方法无法记录，随后转移到植物的其他部位并整合到生物量中。虽然在花盆中未发现荧蒽和苯并[a]芘的含量减少，但检测到1-羟基荧蒽、一种未鉴定的荧蒽化合物和1-甲氧基苯并[a]芘。这些可能是在根中增加的终产物。无法鉴定 Chrysene 的任何转化产物。可以假定大多数代谢物不是在根中合成的，而是根际微生物降解的结果。测试植物显著改善了菲和芘生物转化的条件，并在其根中积累了荧蒽、芘、 Chrysene 和苯并[a]芘。因此可以得出结论，在受污染土壤的生物修复中使用植物是一个有前景的选择。
