State Key Laboratory of Marine Environmental Science of China (Xiamen University), Xiamen 361005, China.
Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China.
Environ Pollut. 2017 Jul;226:135-142. doi: 10.1016/j.envpol.2017.04.025. Epub 2017 Apr 15.
The polycyclic aromatic hydrocarbons (PAHs) located on the epidermal tissues showed distinctive toxic effects to root, while the retention and distribution of PAHs on mangrove seedlings poorly understood. Our results confirmed that the partition coefficients (K) of the PAHs retained on the epidermal tissue of mangrove roots, such as Kandelia obovata, Avicennia marina and Aegiceras corniculatum, were much higher than the Poaceae plants roots, for example wheat and maize (Wild et al., 2005). Moreover, to the parent and alkyl PAHs, a well negative correlation was observed between the surface polarity of these three species of mangrove root and the K values (p < 0.05). To the N/O/S containing PAHs, these relationships were not obviously due to existing of the π-π, n-π interactions and hydrogen bonding between the N/O/S-containing PAHs and epidermal tissues. The PAHs retained on these three species of mangrove root epidermal tissues formed larger clusters than that of on Poaceae plants, such as wheat and maize (Wild et al., 2005) due to the limitation of the suberization of the root exodermis and endodermis. After exposure of 30 d, rhizo- and endophytic bacteria degraded parts of the N/O/S-containing PAHs to medium-lifetime fluorescence substances. To our knowledge, this is the first time to assess the retention of PAHs on the epidermal tissue of mangrove root, which will improve our understanding of the root uptake PAHs process.
多环芳烃 (PAHs) 位于表皮组织中,对根具有明显的毒性作用,而对红树幼苗中 PAHs 的保留和分布知之甚少。我们的结果证实,红树植物根表皮组织中保留的 PAHs(如秋茄、桐花树和白骨壤)的分配系数 (K) 远高于禾本科植物根,如小麦和玉米 (Wild 等人,2005 年)。此外,对于母体和烷基 PAHs,这三种红树植物根的表面极性与 K 值之间存在很好的负相关关系 (p < 0.05)。对于含 N/O/S 的 PAHs,由于 N/O/S 含有的 PAHs 与表皮组织之间存在 π-π、n-π 相互作用和氢键,这些关系不明显。与禾本科植物(如小麦和玉米)相比,这三种红树植物根表皮组织中保留的 PAHs 形成了更大的团簇(Wild 等人,2005 年),这是由于根外表皮和内皮层的栓质化限制了它们的形成。暴露 30 天后,根际和内生细菌将部分含 N/O/S 的 PAHs 降解为中寿命荧光物质。据我们所知,这是首次评估 PAHs 在红树植物根表皮组织中的保留情况,这将有助于我们更好地了解根吸收 PAHs 的过程。