概括
小麦植物将大气中的二氧化碳氧化物纳入纤维素中,但植物的水氧在很大程度上决定了最终的氧同位素比率. 植物水氧是对纤维素氧同位素比率的主要影响.
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
- 生物地质化学生物地质化学
背景情况:
- 纤维素合成是植物的一个基本过程.
- 植物中的氧同位素比率 ((18) O/ ((16) O) 可以反映环境条件.
- 了解植物组织中的氧气来源对于生态和生理学研究至关重要.
研究的目的:
- 调查二氧化碳和水中的氧同位素比对小麦中的纤维素氧同位素比的影响.
- 为了确定在纤维素生物合成过程中二氧化碳和植物水之间氧气交换的程度.
主要方法:
- 在供应的二氧化碳中,小麦植物的种植比例有所不同 (18O/(16) O.
- 纤维素是从小麦植物中净化出来的.
- 纤维素和植物水的氧同位素比率 ((18) O/(16) O) 使用同位素比率质谱法测量.
主要成果:
- 纤维素 (18) O/(16) O比率显示只有很小的差异,尽管二氧化碳 (18) O/(16) O比率的变化很大.
- 观察到的纤维素 (18) O/(16) O比率的差异与植物水的差异非常相似.
- 在纤维素合成过程中,来自二氧化碳的氧气很容易与植物水交换.
结论:
- 植物内部水中的氧同位素比率是控制陆地植物中纤维素的 (18) O/(16) O比率的主导因素.
- 二氧化碳氧气不会直接融入纤维素,而是与水进行完全交换.
- 这一发现对使用植物纤维素作为古气候和古环境重建的代理物有影响.
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