Zhan Di, Liu Yue, Yu Na, Hao Chunbo
Center for Geomicrobiology and Biogeochemistry Research, State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Beijing, China.
School of Earth Sciences and Resources, China University of Geosciences, Beijing, China.
Front Microbiol. 2024 Apr 8;15:1383360. doi: 10.3389/fmicb.2024.1383360. eCollection 2024.
Zinc (Zn) is an essential trace element but can lead to water contamination and ecological deterioration when present in excessive amounts. Therefore, investigating the photosynthetic response of microalgae to Zn stress is of great significance. In this study, we assessed the photosynthetic responses of neutrophilic and acidophilic sp. 1710 to Zn exposure for 96 h. The specific growth rate (μ), chlorophyll-a (Chl-a) content, and chlorophyll fluorescence parameters were determined. The results demonstrated that sp. 1710 was much more tolerant to Zn than , with the half-maximal inhibitory concentration (IC50) values of 225.4 mg/L and 23.4 mg/L, respectively. The μ and Chl-a content of decreased in the presence of 15 mg/L Zn, whereas those of sp. 1710 were unaffected by as high as 100 mg/L Zn. Chlorophyll fluorescence parameters indicated that the regulation of energy dissipation, including non-photochemical quenching, played a crucial role in Zn stress resistance for both strains. However, in the case of , non-photochemical quenching was inhibited by 5 mg/L Zn in the first 48 h, whereas for sp. 1710, it remained unaffected under 100 mg/L Zn. sp. 1710 also exhibited a 20 times stronger capacity for regulating the electron transfer rate than under Zn stress. The light energy utilization efficiency (α) of sp. 1710 had the most highly non-linear correlation with μ, indicating the energy utilization and regulation process of sp. 1710 was well protected under Zn stress. Collectively, our findings demonstrate that the photosystem of sp. 1710 is much more resilient and tolerant than that of under Zn stress.
锌（Zn）是一种必需的微量元素，但过量存在时会导致水污染和生态恶化。因此，研究微藻对锌胁迫的光合响应具有重要意义。在本研究中，我们评估了嗜中性和嗜酸性sp. 1710对锌暴露96小时的光合响应。测定了比生长速率（μ）、叶绿素a（Chl-a）含量和叶绿素荧光参数。结果表明，sp. 1710对锌的耐受性远高于，半最大抑制浓度（IC50）值分别为225.4 mg/L和23.4 mg/L。在15 mg/L锌存在下，的μ和Chl-a含量下降，而sp. 1710在高达100 mg/L锌的情况下不受影响。叶绿素荧光参数表明，能量耗散的调节，包括非光化学猝灭，在两种菌株的抗锌胁迫中起关键作用。然而，对于，在前48小时内，5 mg/L锌抑制了非光化学猝灭，但对于sp. 1710，在100 mg/L锌下仍不受影响。在锌胁迫下，sp. 1710调节电子传递速率的能力也比强20倍。sp. 1710的光能利用效率（α）与μ具有最高的非线性相关性，表明sp. 1710的能量利用和调节过程在锌胁迫下得到了很好的保护。总的来说，我们的研究结果表明，在锌胁迫下，sp. 1710的光合系统比的更具弹性和耐受性。
