Couchat P, Puard M, Lasceve G
Health Phys. 1983 Sep;45(3):757-64. doi: 10.1097/00004032-198309000-00017.
Water vapor exchange between sunflowers (Helianthus annuus L.) and the atmosphere was studied in darkness and in light using THO as a tracer. In the presence of tritiated water vapor, the exchange of THO measured as tritiated water in the leaves was slower in darkness than under illumination. This is explained by the variation of stomatal conductance. The authors show that a single curve is capable of summarizing the tritium exchange under any environmental condition, provided adequate units are used; this curve characterizes the behaviour of sunflowers with regard to tritiated water exchange. Using a numerical simulation model, we showed that the tritiated water vapor exchange is well represented by Fick's equation and affects only 80% of the total leaf water (lamina plus veins).
以THO作为示踪剂，研究了向日葵（Helianthus annuus L.）在黑暗和光照条件下与大气之间的水汽交换。在存在氚化水汽的情况下，以叶片中氚化水形式测量的THO交换在黑暗中比在光照下更慢。这可以通过气孔导度的变化来解释。作者表明，只要使用适当的单位，一条单一曲线就能概括任何环境条件下的氚交换；这条曲线表征了向日葵在氚化水交换方面的行为。使用数值模拟模型，我们表明氚化水汽交换可以很好地用菲克方程表示，并且仅影响叶片总含水量（叶片加叶脉）的80%。
