School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China.
School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China.
Plant Physiol Biochem. 2024 Nov;216:109160. doi: 10.1016/j.plaphy.2024.109160. Epub 2024 Sep 26.
Copper (Cu) and zinc (Zn) are both oxidation-reducing metal elements that are necessary for plant growth, and their effect often depends on their concentration. However, there are few studies that have investigated how plants are stressed and affected when the two ions are present simultaneously, especially when one ion is beneficial due to a low concentration and the other is detrimental due to a high concentration. To address this question, we treated Arabidopsis plants with either high or/and low concentrations of the two ions and investigated their mutual effects and the underlying molecular mechanism, focusing on photosynthetic function. The results showed that the photosynthetic pigment content and the performance of photosynthetic systems were most affected when both metal ions were present at detrimental concentrations (60 μM Cu for Cu and 350 μM Zn for Zn). These include the effective openness of the photoreaction center, the electron transport rate and efficiency of photosystem II (PSII), the NPQ-dependent energy dissipation and the activity of photosystem I (PSI). However, when the harmful concentration of one of the two metals is combined with the beneficial concentration of the other metal (Cu+Zn or Zn+Cu), these photosynthetic indicators are compensated to different degrees but the negative effects of copper ions at high dose are more difficult to eliminate than zinc ions. These results were also confirmed by gene expression analysis, which provides a clue to understanding the interaction between heavy metal ions, reducing metal toxicity and improving the tolerance of plants to heavy metals in practice.
铜（Cu）和锌（Zn）都是氧化还原金属元素，是植物生长所必需的，它们的作用通常取决于其浓度。然而，很少有研究探讨当两种离子同时存在时，植物是如何受到胁迫和影响的，尤其是当一种离子由于浓度低而有益，而另一种离子由于浓度高而有害时。为了解决这个问题，我们用两种离子的高浓度和/或低浓度处理拟南芥植株，并研究了它们的相互作用和潜在的分子机制，重点是光合作用功能。结果表明，当两种金属离子都处于有害浓度（Cu 为 60μM，Zn 为 350μM）时，光合色素含量和光合系统的性能受到的影响最大。这包括光反应中心的有效开度、光系统 II（PSII）的电子传递速率和效率、NPQ 依赖的能量耗散以及光系统 I（PSI）的活性。然而，当两种金属中的一种的有害浓度与另一种金属的有益浓度（Cu+Zn 或 Zn+Cu）结合时，这些光合指标会在不同程度上得到补偿，但铜离子在高剂量下的负面影响比锌离子更难消除。这些结果也得到了基因表达分析的证实，这为理解重金属离子之间的相互作用、降低金属毒性以及提高植物对重金属的耐受性提供了线索。
