Interaction of pretilachlor with photosystem (PS)‐II of the cyanobacterium Desmonostoc muscorum PUPCCC 405.10 has been studied in this paper. Pretilachlor negatively affected growth, chlorophyll a (Chl a), photosynthesis, and carbon dissimilation in a dose‐dependent manner. Effects were also observed in PSs, especially PS‐II (an 11–35% decrease), as well as the whole photosynthetic electron transport activity. The fluorescence emission spectrum of Chl a revealed a dose‐dependent effect of pretilachlor on both the antenna and the core complex of PSs, with more severe effect on the former. Data of O‐J‐I‐P fluorescence transient of Chl a revealed that pretilachlor interfered with electron flow between QA and QB sites of PS‐II. It was further observed that pretilachlor decreased maximum fluorescence, variable and relative variable fluorescence, maximum quantum yield, quantum yield of electron transport, the rate of trapped exciton movement, quantum yield of electron transfer, and performance index of primary photochemistry; however, there was a progressive increase in the net rate of PS‐II closure, quantum yield of energy dissipation, and effective antenna size per active reaction center. A decrease in photosynthetic activity leads to a decrease in carbon dissimilation, as evidenced by low activity of glucose‐6‐phosphate dehydrogenase and pyruvate kinase. Thus, pretilachlor, which is otherwise known to kill weeds by interfering with cell division, affected the growth of the cyanobacteria by interacting with PS‐II.

中文翻译：

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敌草胺与蓝藻 Desmonostoc muscorum PUPCCC 405.10 的 PS-II 活性的相互作用

本文研究了敌草胺与蓝藻 Desmonostoc muscorum PUPCCC 405.10 的光系统 (PS)-II 的相互作用。敌草胺以剂量依赖性方式对生长、叶绿素 a (Chl a)、光合作用和碳异化产生负面影响。在 PSs 中也观察到了影响，尤其是 PS-II（减少了 11-35%），以及整个光合电子传递活动。Chl a 的荧光发射光谱揭示了敌草胺对 PSs 的触角和核心复合物的剂量依赖性影响，对前者的影响更严重。Chl a 的 O-J-I-P 荧光瞬变数据表明，敌草胺干扰了 PS-II 的 QA 和 QB 位点之间的电子流。进一步观察到敌草胺降低了最大荧光、可变和相对可变荧光，最大量子产率、电子传输量子产率、俘获激子运动速率、电子转移量子产率、初级光化学性能指标；然而，PS-II 闭合的净速率、能量耗散的量子产率和每个活性反应中心的有效天线尺寸逐渐增加。光合活性的降低导致碳异化的降低，葡萄糖-6-磷酸脱氢酶和丙酮酸激酶的低活性证明了这一点。因此，已知通过干扰细胞分裂杀死杂草的敌草胺通过与 PS-II 相互作用影响蓝藻的生长。然而，PS-II 闭合的净速率、能量耗散的量子产率和每个活性反应中心的有效天线尺寸逐渐增加。光合活性的降低导致碳异化的降低，葡萄糖-6-磷酸脱氢酶和丙酮酸激酶的低活性证明了这一点。因此，已知通过干扰细胞分裂杀死杂草的敌草胺通过与 PS-II 相互作用影响蓝藻的生长。然而，PS-II 闭合的净速率、能量耗散的量子产率和每个活性反应中心的有效天线尺寸逐渐增加。光合活性的降低导致碳异化的减少，如葡萄糖-6-磷酸脱氢酶和丙酮酸激酶的低活性所证明的。因此，已知通过干扰细胞分裂杀死杂草的敌草胺通过与 PS-II 相互作用影响蓝藻的生长。