Sensitive detection of heavy metal (HM) stress in aquatic plants by dissolved oxygen (DO)-quenched fluorescence/materials movement-induced beam deflection method is demonstrated. Egeria densa Planchon and Cu2+ were used as a model aquatic plant and HM ion, respectively. Reproducibility and experimental errors of the method were first investigated in a control culture solution only containing 10-6 M Ru (II) complex (Tris (2,2'-bipyridyl) ruthenium (II) chloride) without addition of any fertilizer and Cu2+. Changes of DO concentration (∆DO) and deflection (∆DE) during the monitoring periods were used as parameters to quantitatively evaluate the experimental errors and detection limits. Averages or means ([Formula: see text], [Formula: see text]) and standard deviations (σ∆DO, σ∆DE) of ∆DO and ∆DE in seven control experiments with different aquatic plants sheets during both the respiration and photosynthesis processes were obtained. Next, DO and deflection at the middle vicinities of the aquatic plant were monitored during 2 h of both respiration and photosynthesis in presence of 10-10 ~ 10-6 M Cu2+. Experimental results showed that the aquatic plant began to suffer from the HM stress in some extent in presence of 10-9 M Cu2+. When the concentration of Cu2+ was higher than 10-8 M, changing trends of both DO and deflection with time were not reversed during the respiration and photosynthesis, implying that the materials movements in the physiological activities had been altered greatly. It is demonstrated that the method could sensitively detect the HM stress in the aquatic plants given by nM HM ions in culture solution without addition of a fertilizer. Furthermore, detection limits of the method were quantitatively discussed by considering [Formula: see text] σ∆DO and [Formula: see text] σ∆DE as the minimum detectable changes of DO and deflection caused by the HM stress, respectively.

中文翻译：

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溶解氧猝灭荧光/材料运动诱导光束偏转法灵敏检测水生植物重金属胁迫

演示了通过溶解氧（DO）猝灭荧光/材料运动引起的光束偏转方法灵敏检测水生植物中的重金属（HM）胁迫。Egeria densa Planchon 和 Cu2+ 分别用作模型水生植物和 HM 离子。首先在仅含有 10-6 M Ru (II) 复合物（Tris (2,2'-联吡啶基) 氯化钌 (II)）的对照培养液（不添加任何肥料和 Cu2+）中研究该方法的重现性和实验误差。以监测期间溶解氧浓度（ΔDO）和偏转（ΔDE）的变化作为参数来定量评估实验误差和检出限。七个对照实验中不同水生植物在呼吸和呼吸过程中 ΔDO 和 ΔDE 的平均值（[公式：见文本]、[公式：见文本]）和标准差（σΔDO、σΔDE）获得了光合作用过程。接下来，在 10-10 ~ 10-6 M Cu2+ 存在的情况下，在 2 小时的呼吸和光合作用期间监测水生植物中部附近的 DO 和偏转。实验结果表明，在10-9 M Cu2+存在下，水生植物开始受到一定程度的HM胁迫。当Cu2+浓度高于10-8 M时，呼吸和光合作用过程中DO和偏转随时间的变化趋势并未发生逆转，表明生理活动中的物质运动发生了较大改变。结果表明，该方法可以在不添加肥料的情况下，灵敏地检测培养液中nM HM离子对水生植物的HM胁迫。此外，通过将[公式：见正文]σΔDO和[公式：见正文]σΔDE分别视为DO和HM应力引起的挠度的最小可检测变化，定量讨论了该方法的检测限。