Acclimation of leaf respiration temperature responses across thermally contrasting biomes.
Acclimation of leaf respiration temperature responses across thermally contrasting biomes.
复制标题
热对比生物群落中叶子呼吸温度响应的适应。
作者：
Lingling Zhu;K. Bloomfield;S. Asao;M. Tjoelker;John J. G. Egerton;Lucy Hayes;L. Weerasinghe;Danielle Creek;K. Griffin;V. Hurry;M. Liddell;P. Meir;M. Turnbull;O. Atkin
叶片暗呼吸（R-T）的短期温度响应曲线揭示了影响植物净碳交换的关键过程。这包括呼吸特征如何适应环境的持续变化。本研究分析了860条高分辨率R-T（10-70°C范围）曲线：(a)在两个不同季节测量的62种常绿物种，分布在多个野外站点/生物群系；(b)在20/15、25/20和30/25°C（昼/夜）温室中生长的21种（田间取样的亚群）。在田间，在所有站点/季节中，R25（在25°C测量）和R达到最大值的叶t （Tmax）的变化可以用生长t（测量前30天的平均空气t）、太阳辐照度和蒸汽压亏缺来解释，其中生长t的影响最大。R25随生长t的增加而降低，Tmax随季节的增加而增加，只有冬季在低辐照度的寒温带雨林样地例外。温室研究证实了R25和Tmax的热驯化。综上所述：(1)叶片R的热驯化在大多数生物群系中都很常见；(2)当植物面临越来越温暖的气候挑战时，呼吸的高t阈值会动态向上调整。
Short-term temperature response curves of leaf dark respiration (R-T) provide insights into a critical process that influences plant net carbon exchange. This includes how respiratory traits acclimate to sustained changes in the environment. Our study analyses 860 high-resolution R-T (10-70°C range) curves for: (a) 62 evergreen species measured in two contrasting seasons across several field sites/biomes; and (b) 21 species (sub-set of those sampled in the field) grown in glasshouses at 20/15, 25/20 and 30/25 °C (day/night). In the field, across all sites/seasons, variations in R25 (measured at 25 °C) and the leaf-T where R reached its maximum (Tmax ) were explained by growth-T (mean air-T of 30-days prior to measurement), solar irradiance and vapor pressure deficit, with growth-T having the strongest influence. R25 decreased and Tmax increased with rising growth-T across all sites and seasons with the single exception of winter at the cool-temperate rainforest site where irradiance was low. The glasshouse study confirmed that R25 and Tmax thermally acclimated. Collectively, the results suggest: (1) thermal acclimation of leaf R is common in most biomes; and, (2) the high-T threshold of respiration dynamically adjusts upward when plants are challenged with warmer and hotter climates.