Respiration is a crucial process that provides all living organisms with energy and metabolites for growth and cellular maintenance. The processes that control respiration in lichens remain poorly understood. We investigated the effects of short-term temperature changes on the respiration rate, as well as the relative contributions of the cytochrome and alternative pathways of thalli from four green-algal lichen species collected from their natural habitats in Antarctica. Lichen respiration was sensitive to short-term temperature increases over a range of 5–35 °C. The total O2 uptake rate was increased by fourfold, and the mean respiratory coefficient (Q10) decreased from 2.5 to 1.3 as the temperature increased. An increase in temperature from 5 to 15 °C had a positive effect on cytochrome respiration coupled with energy production. Temperatures above 15 °C stimulated the activation of the alternative (energy-dissipating) respiratory pathway. Hyperthermia led to increased O2 consumption that was not associated with mitochondrial oxidases. The effects of increased temperature on the respiration rates were more pronounced in the bipolar lichens Umbilicaria decussata and Usnea sphacelata than in the Usnea aurantiaco-atra species with a narrower geographical distribution.

中文翻译：

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温度对南极地衣细胞色素和替代呼吸途径速率的影响

呼吸是一个至关重要的过程，它为所有生物体提供能量和代谢物，用于生长和细胞维持。控制地衣呼吸的过程仍然知之甚少。我们调查了短期温度变化对呼吸率的影响，以及细胞色素和从南极洲自然栖息地收集的四种绿藻地衣物种的菌体替代途径的相对贡献。地衣呼吸对 5-35°C 范围内的短期温度升高很敏感。随着温度的升高，总的 O2 摄取率增加了四倍，平均呼吸系数 (Q10) 从 2.5 下降到 1.3。温度从 5°C 增加到 15°C 对细胞色素呼吸和能量产生产生积极影响。高于 15 °C 的温度刺激了替代（耗能）呼吸途径的激活。热疗导致 O2 消耗增加，而这与线粒体氧化酶无关。在双极地衣 Umbilicaria decussata 和 Usnea sphacelata 中，温度升高对呼吸率的影响比在地理分布较窄的 Usnea aurantiaco-atra 物种中更为明显。