Abstract
Positron emitters have been used to measure elemental distribution or movement within a sample. This method has been called PET (Positron Emission Tomography) and has been developed especially in medical field. To apply PET for plant samples, several problems have to be taken into account such as positron escape ratio, calibration of the counting rate, etc. The great advantage of this method is that the half-lives of many nuclides are extremely short, in the order of minutes. Therefore, after a few hours, radioactivity of the supplied nuclides is decayed out which allows to repeat the same experiment using the same sample. We present water absorption manner within a plant using 150 labeled water. Though the half-life of 15O is extremely short, 2 minutes, we could determine the real-time amount of water moving within an internode of a soybean plant for the first time.
