树叶温度的亚热带到北极趋同
Brent R Helliker1, Suzanna L Richter
1Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA. helliker@sas.upenn.edu
Nature
|June 13, 2008
概括
树叶温度在整个度范围内惊人地保持不变,这挑战了使用氧同位素比率 (delta(18) O) 进行气候重建的假设. 植物生理学显著影响叶子温度,而不仅仅是环境空气条件.
科学领域:
- 植物生理学 植物生理学
- 同位素地球化学 同位素地球化学
- 气候科学 气候科学
背景情况:
- 纤维素中的氧同位素比 (delta(18) O) 通常用于在植物碳同化过程中推断过去的温度和湿度.
- 一个关键的假设是,在光合作用过程中,叶子和环境空气条件是相同的.
研究的目的:
- 引入一种新的方法来确定树冠树叶温度,使用纤维素三角体{18) O.O.
- 为了研究不同生物体的叶子温度,空气温度和度之间的关系.
主要方法:
- 对来自39种树木的纤维素中氧同位素比率 (delta(18) O) 的分析.
- 通过广泛的度梯度 (从亚热带到北极) 测量叶子温度.
主要成果:
- 在所有研究的度范围内观察到一致的叶子温度为21.4±2.2°C.
- 发现叶子温度明显高于空气温度,特别是在北度,这是由于植物的生理和形态适应.
- 这表明,叶子温度不仅仅取决于环境空气条件.
结论:
- 基于同位素的气候重建的叶子和空气温度等价性假设受到挑战.
- 植物生理生态学对于使用同位素代理来准确解释气候历史至关重要.
- 这些发现可能解释气候对一般叶子经济特征的影响有限.
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