Instituto do Mar da Universidade Federal de São Paulo, Rua Maria Máximo 168, Santos, SP, 11030-400, Brazil; Biosciences Institute, Coastal Campus, State University of São Paulo, Praça Infante Dom Henrique, s/n, São Vicente, SP, 11330-900, Brazil.
Biosciences Institute, Coastal Campus, State University of São Paulo, Praça Infante Dom Henrique, s/n, São Vicente, SP, 11330-900, Brazil.
Aquat Toxicol. 2021 Jan;230:105717. doi: 10.1016/j.aquatox.2020.105717. Epub 2020 Dec 6.
Anthropogenic changes such as ocean acidification, eutrophication, and the release of hazardous chemicals affect coastal environments and aquatic organisms. We investigated the effects of seawater pH (7.4 and 8.2) isolated and in combination with Irgarol on Ulva lactuca. Stress indicators such as membrane damage, lipid peroxidation, and hydrogen peroxide content were assessed. In addition, chlorophyll fluorescence and antioxidant enzyme activities were measured. The photosynthetic yield was affected by low pH in assays with and without Irgarol. However, the combination of low pH and Irgarol promoted photoinhibition, besides the induction of non-photochemical quenching (NPQ) and changes in photosynthetic pigment contents. The induction of NPQ was directly influenced by low pH. The membrane damage was increased in low pH with and without Irgarol exposure. Total soluble protein and carbohydrate contents decreased in low pH, and in presence of Irgarol. The HO content and lipid peroxidation were not affected by low pH. In contrast, Irgarol exposure strongly increased lipid peroxidation in both pHs, suggesting a possible synergistic effect. To avoid the harmful effects of high HO, U. lactuca increased antioxidant enzyme activities in treatments under low pH and in presence of Irgarol. Our results indicate that U. lactuca is tolerant to low pH by inducing NPQ, changing pigment contents, and increasing antioxidant defenses. In contrast, these protective mechanisms could not avoid the harmful effects of the combination with Irgarol.
人为因素引起的变化，如海洋酸化、富营养化和危险化学品的释放，会影响沿海环境和水生生物。我们研究了海水 pH 值（7.4 和 8.2）单独和与 Irgarol 结合对浒苔的影响。评估了膜损伤、脂质过氧化和过氧化氢含量等应激指标。此外，还测量了叶绿素荧光和抗氧化酶活性。在有和没有 Irgarol 的情况下，低 pH 值都会影响光合作用产量。然而，低 pH 值和 Irgarol 的组合除了诱导非光化学猝灭（NPQ）和光合色素含量变化外，还促进了光抑制。NPQ 的诱导直接受到低 pH 值的影响。在有和没有 Irgarol 暴露的情况下，低 pH 值会增加膜损伤。低 pH 值和 Irgarol 存在都会降低总可溶性蛋白和碳水化合物含量。低 pH 值不会影响 HO 含量和脂质过氧化，但 Irgarol 暴露会在两种 pH 值下强烈增加脂质过氧化，表明可能存在协同作用。为了避免高 HO 的有害影响，浒苔在低 pH 值和 Irgarol 存在的处理中增加了抗氧化酶活性。我们的结果表明，浒苔通过诱导 NPQ、改变色素含量和增加抗氧化防御来耐受低 pH 值。相比之下，这些保护机制无法避免与 Irgarol 结合的有害影响。
