Zundel G, Miekeley W, Grisi B M, Förstel H
Radiat Environ Biophys. 1978 Aug 10;15(2):203-12. doi: 10.1007/BF01323265.
The H2(18O) enrichment, delta, in the water of leaves from four Brazilian trees, was studied. In all trees the leaf water showed a periodic variation in delta, with a maximum in the early afternoon and a minimum around 6 a.m. In general delta was found to be either higher or lower than the stationary enrichment which is supposed to depend only on the relative atmospheric humidity. This effect is due to the slow response of the system to variations of the humidity. For a special case, where steady-state conditions could be anticipated, the kinetic enrichment was obtained to 20 +/- 3%, which agrees with theoretical predictions.
对巴西四种树木叶片水分中的H2(18O)富集度δ进行了研究。在所有树木中，叶片水分的δ呈现周期性变化，午后早些时候达到最大值，凌晨6点左右达到最小值。总体而言，发现δ高于或低于假定仅取决于相对大气湿度的静态富集度。这种效应是由于系统对湿度变化的响应缓慢所致。对于一种可以预期稳态条件的特殊情况，获得的动力学富集度为20±3%，这与理论预测相符。
