Enhanced toxicity to the cyanobacterium Microcystis aeruginosa by low-dosage repeated exposure to the allelochemical N-phenyl-1-naphthylamine
Enhanced toxicity to the cyanobacterium Microcystis aeruginosa by low-dosage repeated exposure to the allelochemical N-phenyl-1-naphthylamine
复制标题
低剂量重复接触化感化学 N-苯基-1-萘胺，增强对蓝藻铜绿微囊藻的毒性
DOI：
10.1016/j.chemosphere.2017.01.102
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发表时间：
2017
期刊：
影响因子：
8.8
通讯作者：
Z.B.Wu
中科院分区：
文献类型：
--
作者：
Y.N.Gao;F.J.Ge;L.P.Zhang;Y.He;Z.Y.Lu;B.Y.Liu;Q.H.Zhou;Z.B.Wu
植物是否能通过释放低浓度的化感物质对目标生物产生强烈的化感抑制作用，以及如何发挥这种作用，一直是个令人困惑的问题。植物化感物质被认为是持续释放的，然而，迫切需要来自特定化感物质的直接证据。比较了两种不同暴露方式下，化感物质N-苯基-1-萘胺（NPN）对好氧微囊藻的毒性。一种是低剂量重复暴露（LRE），其中50 μg L− 1 NPN重复给药以模拟化感物质的持续释放，另一种是高剂量单次暴露（HSE），按照常规毒性测定。结果表明，LRE组对铜绿微囊藻的生长有明显的抑制作用，第6 ~ 9天的抑制率达90%以上。细胞膜损伤率从第5天的64.05%增加到第9天的96.60%。PS Ⅱ光合活性（Fv/Fm、Φ PS Ⅱ、NPQ和ETRmax）也受到抑制。HSE处理组的铜绿假单胞菌生长和PSII光合活性最初受到抑制，但从第4、5天开始逐渐恢复，同时培养液中NPN含量持续下降。虽然LRE组的NPN含量相对较低，但在整个实验过程中保持在较稳定的水平。这些结果表明，水生植物持续释放低剂量的化感物质在其对蓝藻的有效抑制中起着至关重要的作用。低剂量持续暴露模式有待进一步研究。
It has been puzzling whether and how a plant could exert a strong allelopathic inhibition to the target organisms by releasing low concentrations of allelochemicals. Plant allelochemicals have been proposed to be released continuously, however, direct evidence from specific allelochemicals is urgently required. In the present study, the toxicity of allelochemicalN-phenyl-1-naphthylamine (NPN) towards the cyanobacteriumMicrocystis aeruginosaby two different exposure patterns was compared. One was low-dosage repeated exposure (LRE), in which 50 μg L−1NPN was repeatedly dosed to simulate the continual release of allelochemicals, and the other one was high-dosage single exposure (HSE) as per the routine toxicity assay. The results showed a significant growth inhibition toM. aeruginosain the LRE group, where the inhibition rate reached above 90% from day 6 to day 9. The cell-membrane damage ratio increased from 64.05% on day 5 up to 96.60% on day 9. PSII photosynthesis activity expressed as Fv/Fm, ΦPSII, NPQ and ETRmax was also thoroughly inhibited in this group. Whereas the growth and PSII photosynthesis activity ofM. aeruginosain the HSE group were inhibited initially, but recovered gradually from day 4 or 5, which was accompanied by a continuous reduction of NPN content in culture solutions. Although NPN content in the LRE group was relatively lower, it remained at a more stable level throughout the experiment. These results indicate that continual release of low-dosage allelochemicals by aquatic plants plays crucial roles in their potent inhibition against cyanobacteria. Low-dosage continual exposure pattern needs to be investigated further.