Istituto per lo Studio dei Materiali Nanostrutturati Sede Sapienza, Consiglio Nazionale delle Ricerche, P. le Aldo Moro 5, 00185 Rome, Italy.
Dipartimento di Scienze e Tecnologie per l'Agricoltura, le Foreste, la Natura e l'Energia, Università degli Studi della Tuscia, 01100 Viterbo, Italy.
Biosensors (Basel). 2022 Jan 25;12(2):67. doi: 10.3390/bios12020067.
The widespread agricultural use of the phenylurea herbicide Diuron (DCMU) requires the investigation of ecotoxicological risk in freshwater and soil ecosystems in light of potential effects on non-target primary producers and a heavier effect on higher trophic levels. We used microalgae-based fluorimetric bioassays for studying the interferences on the photosynthesis of a freshwater and soil model green microalga () induced by environmentally relevant concentrations of the herbicide DCMU. Measurements of steady-state chlorophyll (Chl-a) fluorescence emission spectra were performed; as well, the kinetics of the Chl-a fluorescence transient were recorded. Percentage indexes of interference on photosynthesis were calculated after comparison of steady-state and kinetic Chl-a fluorescence measurements of DCMU-exposed and control cell suspensions. The results obtained after 30 min exposure to the herbicide DCMU confirmed a significant inhibitory effect of DCMU 2 μg/L, and no significant differences between %ι values for DCMU 0.2 μg/L and 0.02 μg/L exposures. Positive %ε values from kinetic measurements of the Chl-a fluorescence transient confirmed the same interfering effect of 2 μg/L DCMU on PSII photochemistry in the exposed cell suspensions. Negative values of %ε observed for 0.2 and 0.02 μg/L DCMU exposures could be attributable to a presumptive 'stimulatory-like' effect in the photochemistry of photosynthesis. Short-term exposure to sub-μg/L DCMU concentration (≤0.2 μg/L) affects the photosynthetic process of the model microalga . Similar environmental exposures could affect natural communities of unicellular autotrophs, with hardly predictable cascading secondary effects on higher trophic levels.
广泛应用于农业领域的苯脲类除草剂敌草隆（DCMU），需要根据其对非靶标初级生产者的潜在影响以及对更高营养级别的更严重影响，调查其对淡水和土壤生态系统的生态毒性风险。我们使用基于微藻的荧光生物测定法，研究了环境相关浓度的除草剂敌草隆（DCMU）对淡水和土壤模式绿藻（）光合作用的干扰。我们进行了稳态叶绿素（Chl-a）荧光发射光谱的测量；同时，记录了 Chl-a 荧光瞬变的动力学。通过比较暴露于敌草隆和对照细胞悬浮液的稳态和动力学 Chl-a 荧光测量值，计算了光合作用干扰的百分率指数。在暴露于除草剂敌草隆 30 分钟后获得的结果证实，敌草隆 2μg/L 具有显著的抑制作用，而敌草隆 0.2μg/L 和 0.02μg/L 暴露的%ι 值之间没有显著差异。Chl-a 荧光瞬变动力学测量的正%ε 值证实了 2μg/L 敌草隆对暴露细胞悬浮液中 PSII 光化学的相同干扰作用。对于 0.2 和 0.02μg/L 敌草隆暴露，观察到的负%ε 值可能归因于光合作用光化学中的假定“刺激样”作用。短期暴露于亚μg/L 敌草隆浓度（≤0.2μg/L）会影响模式微藻的光合作用过程。类似的环境暴露可能会影响单细胞自养生物的自然群落，对更高营养级别的级联二次效应几乎难以预测。
