天花板温度大大高估了热带树木的叶子热安全边缘
Olivier Jean Leonce Manzi1,2, Maria Wittemann1, Mirindi Eric Dusenge1,3
1Department of Biological and Environmental Sciences, University of Gothenburg, PO Box 463, Gothenburg, SE-405 30, Sweden.
The New phytologist
|July 29, 2024
概括
叶子温度 (T叶子) 在热带树木中可以超过树冠温度 (Tcan) 高达20°C,突出显示光合作用的风险. 依赖树冠温度低估了植物热应激,这对于了解植物温度调节至关重要.
科学领域:
- 植物生理学 植物生理学
- 生态生态学 生态生态学
- 气候变化生物学
背景情况:
- 植物的温度反应对生存和生产力至关重要.
- 空气温度是叶子温度 (T叶子) 的一个糟糕的代理,它直接影响生理过程.
- 树冠温度 (Tcan) 经常被使用,但可能不反映细度T叶变化.
研究的目的:
- 调查热带树木种植园中叶子温度 (T叶子) 和树冠温度 (T可以) 之间的差异.
- 量化叶子温度与空气温度的偏差 (ΔT叶子) 以及它们对热应激的影响.
- 评估叶子特征在温度调节和耐热性中的作用.
主要方法:
- 红外辐射测量用于测量多种热带树种植园中的T叶和T可.
- 测量是在卢旺达的一个海拔和温度梯度上进行的.
- 与空气温度的偏差 (ΔT叶子和 ΔT可以) 与叶子特征和环境条件相关分析.
主要成果:
- 暴露在阳光下的叶子达到高温 (高达50°C),与空气温度有显著的偏差 (叶子的ΔT,平均为8-10°C,高达20°C).
- 测量T叶子和ΔT叶子值经常接近或超过临界光合作用耐热值.
- Tcan 和 ΔTcan 始终低估了实际的叶子温度和热应力,导致过高估计的热安全边缘.
结论:
- 叶子温度 (T叶子) 可以大大高于树冠温度 (Tcan),对热带森林中的植物光合作用构成重大风险.
- 叶子的特征,如口腔导电性和叶子大小,在叶子温度调节中起着至关重要的作用.
- 仅仅监测树冠温度是不足以准确评估单个叶子所经历的热应激,因此需要直接测量叶子温度以进行精确的生态和生理研究.
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