Herbicides interfere with antigrazer defenses in Scenedesmus obliquus
Herbicides interfere with antigrazer defenses in Scenedesmus obliquus
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除草剂干扰斜生栅藻的抗食草防御
DOI：
10.1016/j.chemosphere.2016.07.087
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发表时间：
2016
期刊：
影响因子：
8.8
通讯作者：
Yang Zhou
中科院分区：
文献类型：
--
作者：
Zhu Xuexia;Sun Yunfei;Zhang Xingxing;Heng Hailu;Nan Haihong;Zhang Lu;Huang Yuan;Yang Zhou
除草剂的广泛应用导致了除草剂污染对水生生态系统的严重威胁。除草剂暴露不仅通过对单个物种施加毒性，而且通过改变种间相互作用来影响水生群落。本研究调查了常见的绿色藻类栅藻（Scenedesmus）对不同浓度（0-2.0 mg L−1）的不同除草剂[草甘膦、2，4-二氯苯氧乙酸（2，4-D）和莠去津]的抗食草防御。在食草动物（水蚤）来源的线索的存在下，没有除草剂的S. aerobus种群形成了高比例的多细胞（例如，四细胞和八细胞）菌落。这一结果证实了S. arthus对放牧风险表现出形态防御。在0.002-0.02 mg L−1的低浓度范围内，3种除草剂对紫球藻的生长和光合效率没有影响，多细胞菌落比例保持恒定。在0.20-2.0 mg L−1的高浓度范围内，阿特拉津显著抑制藻类生长和光合作用，而草甘膦或2，4-D则没有。尽管如此，草甘膦或2，4-D的这些水平显著降低了多细胞集落的比例，Daphniafiltrate处理群体中每个颗粒的细胞数量减少。在0.20-2.0 mg L− 1的阿特拉津处理后，尽管加入了Daphniafiltrate，但没有形成八细胞集落。这些结果表明，除草剂暴露损害antigrazer殖民形态的浮游植物，虽然它是不足以阻碍藻类生长。这种现象会增加食草动物捕食的风险，从而破坏可诱导的浮游植物群落。此外，食草动物和浮游植物之间的捕食者-被捕食者的相互作用可能会发生比以前认为的更严重的变化。
The extensive application of herbicides has led to a serious threat of herbicide contamination to aquatic ecosystem. Herbicide exposure affects aquatic communities not only by exerting toxicity on single species but also by changing interspecific interactions. This study investigated the antigrazer defenses of the common green algaScenedesmus obliquusagainst different herbicides [glyphosate, 2,4-dichlorophenoxyacetic acid (2,4-D), and atrazine] at various concentrations (0–2.0 mg L−1). In the presence of grazer (Daphnia)-derived cues,S. obliquuspopulations without herbicides formed high proportions of multicelled (e.g., four- and eight-celled) colonies. This result confirms thatS. obliquusexhibits a morphological defense against grazing risk. At the low concentration range of 0.002–0.02 mg L−1, the three herbicides exerted no influence on the growth and photosynthetic efficiency ofS. obliquus, and multicelled colonies showed constant proportions. At the high concentration range of 0.20–2.0 mg L−1, atrazine significantly inhibited the algal growth and photosynthesis whereas glyphosate or 2,4-D did not. Nonetheless, these levels of glyphosate or 2,4-D remarkably decreased the proportion of multicelled colonies, with reduced numbers of cells per particle inDaphniafiltrate-treated population. No eight-celled colony was formed after treatment with atrazine at 0.20–2.0 mg L−1despite the addition ofDaphniafiltrate. These results suggest that herbicide exposure impairs antigrazer colonial morphs in phytoplankton although it is not sufficient to hamper algal growth. This phenomenon can increase the risk of predation by herbivores, thereby disrupting the inducible phytoplankton community. Furthermore, the predator-prey interactions between herbivores and phytoplankton can be potentially changed more seriously than previously considered.