PREDICTION OF THE FLUX OF TRITIATED-WATER FROM AIR TO PLANT-LEAVES

A tentative model was developed to predict the flux of tritiated water [THO] vapor from air to plant leaves, in relation to leaf stomatal resistance and temperature. The validity of this model was investigated by field experiments performed in autumn and spring, to meet different meteorological and physiological conditions. In these experiments, grape leaves were exposed to a constant level of THO vapor. Foliar samples were collected at different times during and after exposure and were analyzed for their 3H content. The 3H concentrations found in leaf tissue-water are in good agreement with the theoretical estimations, which indicates that the model is probably adequate for the description of THO movement and distribution.