Organically bound tritium in wheat after short-term exposure to atmospheric tritium under laboratory conditions

The uptake, loss, conversion and translocation of tritium in wheat plants were determined following a unique short-time exposure to atmospheric tritium under laboratory conditions. Potted plants were exposed between anthesis and maturity, under day-time conditions at two different light intensities and during night conditions. Two data sets with exposure conditions and corresponding tritium concentrations in plants are given for use in appropriate models. In leaves, the tritium uptake into tissue water was about four times lower under night conditions than under day conditions. The initial relative concentrations of organically bound tritium in leaves observed under night conditions were about 50% of those observed under day conditions. Translocation of organically bound tritium to grain was found to depend on the growth rate of the grain. Once translocation to grain has taken place, organically bound tritium is lost only slowly.