氧和稳定同位素之间的共变量沿着从西伦水到木纤维素的道路沿着干旱度梯度下降
Meisha Holloway-Phillips1,2, Lucas A Cernusak3, Daniel B Nelson1
1Department of Environmental Sciences-Botany, University of Basel, 4056, Basel, Switzerland.
The New phytologist
|September 8, 2023
概括
了解植物纤维素中的氧和同位素对于环境推断至关重要. 这项研究揭示了它们的共变性如何从水变为木材,影响气候重建.
科学领域:
- 植物生物学 植物生物学
- 同位素地质化学 同位素地质化学
- 环境科学环境科学
背景情况:
- 植物纤维素中的氧气 (δ18O) 和 (δ2H) 同位素是重建过去环境条件的关键代理,特别是来自树环.
- 植物纤维素中δ18O和δ2H之间的共变以及它与降水等环境因素的关系仍然不完全理解.
研究的目的:
- 通过干旱度梯度研究植物水和纤维素中 δ18O 和 δ2H 之间的关系.
- 为了检查这种共变如何从西勒姆水变为叶子和树枝纤维素.
- 评估平均年降水 (MAP) 对这些同位素关系的影响.
主要方法:
- 在植物水,叶子纤维素和树枝木纤维素中比较同位素成分 (δ18O和δ2H).
- 在澳大利亚北部的自然干旱梯度上采样占主导地位的树种.
- 与MAP相关的同位素共变和丰富 (Δ) 的分析.
主要成果:
- 观察到同位素协同变化的下降,从树叶水到树叶水,再到树叶和树枝纤维素.
- 叶子水中的同位素丰富部分保留在叶子纤维素中,但不在枝木纤维素中.
- 虽然 δ2H 显示了叶子和树枝之间的良好相关性,但 δ18O 显示了随着 MAP 的下降而增加的偏移.
结论:
- 在纤维素中,光合作用后与水的氧气同位素交换是显著的,这使得从 δ18O 的直接气候推断变得复杂.
- 可变的动力和非平衡同位素效应使解释对δ2H模式的代谢影响变得复杂.
- 考虑氧同位素交换对于使用 δ18O 准确地重建古气候至关重要;比较 δ2H 和 δ18O 可能会揭示代谢变化.
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