夜间的糖糖不像预期的那样反映了叶子中的过渡性粉的同位素组成
A Wacker1, D B Nelson1, G Tcherkez2,3
1Department of Environmental Sciences, University of Basel, Basel, Switzerland.
Plant biology (Stuttgart, Germany)
|April 28, 2025
概括
糖的同位素组成 (δ2H) 尽管粉重新调动,但每天不变. 这表明,在一个时间点估计糖 δ2H 在稳定状态条件下足以进行植物研究.
科学领域:
- 植物生理学 植物生理学
- 稳定同位素生物地质化学
- 植物新陈代谢 植物新陈代谢
背景情况:
- 纤维素的同位素组成 (δ2H) 反映了叶子中糖的合成.
- 白天的砂糖来源于卡尔文-本森-巴什姆循环,而夜间的砂糖来自重新调动的粉.
- 粉与三酸相比,自然是2H贫乏的,这意味着糖 δ2H的日间变化.
研究的目的:
- 为了研究植物中糖和粉 δ2H 的日间变化.
- 为了测试沙糖 δ2H 值因光合作用代谢而每天有所变化的假设.
- 为了确定与糖糖生物合成 (ε_糖) 相关的明显同位素分离.
主要方法:
- 在豆类,卜和向日中测量糖和粉 δ2H.
- 控制的气候和稳定态同位素条件.
- 对粉降解和2H-减耗相对于糖糖的分析.
主要成果:
- 叶子粉具有显著的2H贫乏 (约2H) 含量. 90‰) 与白天的糖糖相比.
- 在不同物种中,没有观察到夜间糖 δ2H 的每日显著变化.
- 显而易见的同位素分离 (ε_糖) 是白天和晚上一致的 (-140 ‰ 到 -180 ‰).
结论:
- 每日糖糖 δ2H 的变化是最小的,与基于粉代谢的预期相反.
- 糖糖/粉动态的特定物种差异可能会影响同位素信号.
- 在一个单一的时间点估计 ε_sucrose 对于稳定状态条件来说是足够的;对于复杂的信号,需要位置特定的分析.
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