同位素稳定状态或非稳定状态的透气? 来自全树室的洞察力
Richard Harwood1, Lucas A Cernusak2, John E Drake3
1School of Life and Environmental Sciences, The University of Sydney, Private Bag 4011, Narellan, NSW 2567, Australia.
Tree physiology
|October 4, 2024
概括
这项研究发现,白树很少在同位素稳定状态下全天发汗. 然而,在更长的时间内,透气的水蒸气的氧同位素组成接近源水的成分.
科学领域:
- 植物生理学 植物生理学
- 同位素水文学 同位素水文学
- 森林生态森林生态学
背景情况:
- 了解透气是植物生理学和水循环研究的关键.
- 透气水蒸气 (δE) 的氧同位素组成是水源的潜在指标.
- 之前的研究已经假定了 δE 的同位素稳定状态,但这在整个树尺度上仍然未经测试.
研究的目的:
- 为了研究来自树的透气水蒸气 (δE) 中氧同位素组成的迪尔动力学.
- 为了测试在整个树层面对 δE 的同位素稳定状态的假设.
- 评估温度升高对 δE 的影响.
主要方法:
- 使用了12个整个树的房间与Eucalyptus parramattensis.
- 同时测量了 δE,温度和气体交换.
- 实施的环境和+3°C升温处理.
主要成果:
- 每日平均 δE 值接近源水 (δ源) 在 1.2 ‰.
- 在 δE 中观察到显著的滴值变化.
- 树木在24小时的时间内并不始终处于同位素稳定状态.
结论:
- 对于欧树中 δE 的恒定同位素稳定状态的假设在 diel 时间表上没有支持.
- 透气的同位素组成在很长一段时间内接近源水.
- 在未来的透气同位素研究中,应考虑 δE 的值波动.
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