Temperature is one of the key abiotic factors during the life of plants, especially in the Arctic region which is currently experiencing rapid climate change. We evaluated plant traits and environmental variables determining leaf temperature in tundra shrubs and volatile organic compound (VOC) emissions with field measurements on deciduous tundra shrubs, Salix myrsinites and Betula nana, and evergreen Cassiope tetragona and Rhododendron lapponicum. Higher leaf-to-air temperature difference was observed in evergreen, compared to deciduous shrubs. Evergreen shrubs also showed continuously increasing photosynthesis with increasing temperature, suggesting high thermal tolerance. For the deciduous species, the optimum temperature for net photosynthesis was between our measurement temperatures of 24 °C and 38 °C. Air temperature and vapor pressure deficit were the most important variables influencing leaf temperature and VOC emissions in all the studied plants, along with stomatal density and specific leaf area in the deciduous shrubs. Using climate data and emission factors from our measurements, we modelled total seasonal tundra shrub VOC emissions of 0.3–2.3 g m⁻² over the main growing season. Our results showed higher-than-expected temperature optima for photosynthesis and VOC emission and demonstrated the relative importance of plant traits and local environments in determining leaf temperature and VOC emissions in a subarctic tundra.

温度是植物生命过程中的关键非生物因素之一，特别是在目前正在经历快速气候变化的北极地区。我们通过对落叶苔原灌木、沙柳和桦木、常绿仙后和杜鹃进行现场测量，评估了决定苔原灌木叶片温度和挥发性有机化合物 (VOC) 排放的植物性状和环境变量。与落叶灌木相比，常绿植物的叶与空气温差更高。常绿灌木还表现出随着温度升高而不断增强的光合作用，表明其具有较高的耐热性。对于落叶树种来说，净光合作用的最佳温度在我们的测量温度 24 °C 到 38 °C 之间。气温和蒸气压不足是影响所有研究植物的叶片温度和挥发性有机化合物排放的最重要变量，以及落叶灌木的气孔密度和比叶面积。利用我们测量的气候数据和排放因子，我们模拟了主要生长季节苔原灌木 VOC 总季节性排放量为 0.3–2.3 gm ^-2 。我们的结果显示光合作用和 VOC 排放的最佳温度高于预期，并证明了植物性状和当地环境在确定亚北极苔原叶片温度和 VOC 排放方面的相对重要性。