There is scarce investigation addressing interpopulation tolerance responses to address the influence of a history of chronic stress exposure, as that occurring in polluted environments, in photoautotrophs. We evaluated ecophysiological (photosynthetic activity) and metabolic (oxidative stress and damage) responses of two populations of green macroalga Ulva compressa from polluted (Ventanas) and non-polluted (Cachagua) localions of central Chile, and exposed to controlled hypersalinity conditions of 32 (control), 42, 62 and 82 psu (practical salinity units) for 6 h, 48 h and 6 d. Both primary production (ETR_max) and photosynthetic efficiency (α_ETR) were generally higher in the population from Cachagua compared to Ventanas at all times and salinities. Moreover, at most experimental times and salinities the population from Ventanas had greater levels of H₂O₂ and lipid peroxidation that individuals from Cachagua. Total ascorbate was higher in the population of Cachagua than Ventanas at 42 and 82 psu after 6 and 48 h, respectively, while at 6 d concentrations were similar between both populations at all salinities. Total glutathione was greater in both populations after 6 h at all salinities, but at 48 h its concentrations were higher only in the population from Cachagua, a trend that was maintained at 6 d under 82 psu only. Reduced and oxidized ascorbate (ASC and DHA, respectively) and glutathione (GSH and GSSG, respectively) demonstrated similar patterns between U. compressa populations, with an increase oxidation with greater salinities but efficient recycling to maintain sufficient batch of ASC and GSH. When assessing the expression of antioxidant enzymes catalase (CAT), superoxide dismutase (SOD) and dehydroascorbate reductase (DHAR), while the population of Ventanas displayed a general trend of upregulation with increasing salinities along the experiments, U. compressa from Cachagua revealed patterns of downregulation. Results demonstrated that although both populations were still viable after the applied hypersalinities during all experimental times, biological performance was usually more affected in the population from the Ventanas than Cachagua, likely due to a depressed baseline metabolism after a long history of exposition to environmental pollution.

缺乏针对种群间耐受性反应的研究，以解决在光养生物中在污染环境中发生的慢性应激暴露史的影响。我们评估了智利中部受污染（Ventanas）和无污染（Cachagua ）的两个绿巨藻Ulva compressa种群的生态生理学（光合活性）和代谢（氧化应激和破坏）响应，并暴露于32（对照），42、62和82 psu（实用盐度单位）持续6 h，48 h和6 d。初级生产（ETR _max）和光合效率（_αETR）在所有时间和盐度下，卡恰瓜的人口通常都比维塔纳斯人高。此外，在大多数实验时间和盐度下，维塔纳斯州的人口中H ₂ O _2的含量更高和来自卡恰瓜的脂质过氧化。在6和48小时后，卡查瓜种群中的总抗坏血酸含量分别高于42和82 psu，高于维塔纳斯，而在6 d时，所有盐度的两个种群之间的总抗坏血酸浓度相似。在所有盐度下6 h后，两个种群中的总谷胱甘肽都较高，但在48 h时，其浓度仅在来自Cachagua的种群中较高，这一趋势仅在82 psu下维持6 d。还原型和氧化型抗坏血酸盐（分别为ASC和DHA）和谷胱甘肽（分别为GSH和GSSG）在U. compressa之间表现出相似的模式人口中，氧化增加，盐度增加，但有效回收以维持足够数量的ASC和GSH。当评估抗氧化酶过氧化氢酶（表达CAT），超氧化物歧化酶（SOD）和脱氢还原酶（DHAR），而本塔纳斯的人口显示上调的一个总的趋势沿实验增加的盐度，U.牛鞭来自卡查瓜的消息揭示了下调的模式。结果表明，尽管在所有实验时间内施加高盐度后，这两个种群仍然可行，但从Ventanas种群中获得的生物学性能通常比Cachagua受到的影响更大，这可能是由于长期暴露于环境污染后基线代谢下降所致。