Flanagan L B, Ehleringer J R
Department of Biology and Stable Isotope Ratio Facility for Environmental Research, University of Utah, Salt Lake City, Utah 84112.
Plant Physiol. 1991 Sep;97(1):298-305. doi: 10.1104/pp.97.1.298.
In this paper we make comparisons between the observed stable isotopic composition of leaf water and the predictions of the Craig-Gordon model of isotopic enrichment when plants (Cornus stolonifera L.) were exposed to natural, diurnal changes in temperature and humidity in a glasshouse. In addition, we determined the effects of mild water stress on the isotopic composition of leaf water. The model predicted different patterns of diurnal change for the oxygen and hydrogen isotopic composition of leaf water. The observed leaf water isotopic composition followed qualitatively similar patterns of diurnal change to those predicted by the model. At midday, however, the model always predicted a higher degree of heavy isotope enrichment than was actually observed in leaves. There was no effect of mild water stress on the hydrogen isotopic composition of leaf water. For the oxygen isotopic composition of leaf water, there was either no significant difference between control and water-stressed plants or the stressed plants had lower delta(18)O values, despite the enriched stem water isotopic composition observed for the stressed plants.
在本文中，我们对温室中植物（偃伏梾木）在自然昼夜温度和湿度变化条件下，叶片水的实测稳定同位素组成与同位素富集的克雷格 - 戈登模型预测结果进行了比较。此外，我们还测定了轻度水分胁迫对叶片水同位素组成的影响。该模型预测了叶片水氧和氢同位素组成的不同昼夜变化模式。实测的叶片水同位素组成在昼夜变化模式上与模型预测的在性质上相似。然而，在中午时，该模型总是预测出比叶片实际观测到的更高程度的重同位素富集。轻度水分胁迫对叶片水的氢同位素组成没有影响。对于叶片水的氧同位素组成，对照植株和水分胁迫植株之间要么没有显著差异，要么尽管在水分胁迫植株中观测到茎水同位素组成富集，但胁迫植株的δ(18)O值更低。
