Thermal plasticity of photosynthesis: the role of acclimation in forest responses to a warming climate
Thermal plasticity of photosynthesis: the role of acclimation in forest responses to a warming climate
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DOI：
10.1111/j.1365-2486.2009.02090.x
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发表时间：
2010-08-01
影响因子：
11.6
通讯作者：
Edwards, Nelson T.
中科院分区：
文献类型：
--
作者：
Gunderson, Carla A.;O'Hara, Keiran H.;Edwards, Nelson T.
对气候变化预测至关重要的气温不断上升，可能会超过碳增益的最佳温度，从而改变森林生态系统的功能和结构。预计这些变化将威胁敏感物种的生存，导致局部灭绝、范围迁移和森林组成的改变。本文研究了枫香、红栎、镰叶栎、赤桦和巨齿杨等5种落叶树种的光合作用对温度的敏感性及其与气候种源的适应潜力。开顶室在3年内提供三个级别的升温（高于环境温度+0、+2和+4摄氏度），跟踪自然温度变化。在所有处理中，CO2同化的最适温度与白天温度密切相关，但在这些最适温度下的同化率是可比的。在所有物种中确认了热最适调节，无论温度是否随季节或处理而变化，并且无论植物材料的物种范围或种源中的气候如何。观察到17度至34度的最适温度。在不同的物种，驯化潜力变化从0.55摄氏度至1.07摄氏度每度的变化在白天的温度。对温度操纵的反应与在成熟的本土树木中观察到的季节性适应没有不同，这表明光合作用的反应不应该使用静态温度函数来建模，但应该包括调整来适应。观察到的高度动态平衡表明，气候变暖对森林生产力，物种生存和范围限制的直接影响可能小于现有模型的预测。
The increasing air temperatures central to climate change predictions have the potential to alter forest ecosystem function and structure by exceeding temperatures optimal for carbon gain. Such changes are projected to threaten survival of sensitive species, leading to local extinctions, range migrations, and altered forest composition. This study investigated photosynthetic sensitivity to temperature and the potential for acclimation in relation to the climatic provenance of five species of deciduous trees, Liquidambar styraciflua, Quercus rubra, Quercus falcata, Betula alleghaniensis, and Populus grandidentata. Open-top chambers supplied three levels of warming (+0, +2, and +4 degrees C above ambient) over 3 years, tracking natural temperature variability. Optimal temperature for CO2 assimilation was strongly correlated with daytime temperature in all treatments, but assimilation rates at those optima were comparable. Adjustment of thermal optima was confirmed in all species, whether temperatures varied with season or treatment, and regardless of climate in the species' range or provenance of the plant material. Temperature optima from 17 degrees to 34 degrees were observed. Across species, acclimation potentials varied from 0.55 degrees C to 1.07 degrees C per degree change in daytime temperature. Responses to the temperature manipulation were not different from the seasonal acclimation observed in mature indigenous trees, suggesting that photosynthetic responses should not be modeled using static temperature functions, but should incorporate an adjustment to account for acclimation. The high degree of homeostasis observed indicates that direct impacts of climatic warming on forest productivity, species survival, and range limits may be less than predicted by existing models.