Uptake kinetics of deuteriated water vapor by plants: Experiments of D2O release in a greenhouse as a substitute for tritiated water

Pelted plants were exposed to D2O vapor in a greenhouse and uptake of D2O b y leaf and deposition of D2O to pot soil were examined. Atmospheric D2O con centration in the greenhouse increased rapidly after starting the release a nd reached constant level in a few hours. Although the variation of D2O con centration in leaf followed that in air with showing a time delay, D2O conc entration in leaf did not become the same level as that in air and vein sho wed lower concentration than lamina. D2O concentration in the pot soil incr eased slowly with diffusing in deeper layer.