Analysis Of Transportation And Distribution Of Photosynthates In Hemp With The Positron-Emitting Tracer Imaging System

Abstract

The photosynthates required for vegetative growth are transported mainly to the root and stem, while those required for reproductive growth are transported to the fruits and seeds. However, few studies have analyzed the transportation and distribution from captured moving image.
To analyze the behavior of photosynthates in an extending stem in real time, we used the positron-emitting tracer imaging system (PETIS). Hemp was employed because it grows very rapidly. With a mathematical analysis, we estimated the unloading rates of the tracer in the respective selected regions of interest in the obtained image. After supplying the largest expanded leaf with ¹¹CO₂, the ¹¹C-tracer was preferentially accumulated in the growing internode just below the leaf and to the shoot apex. When ¹¹CO₂ was supplied to a lower leaf, the ¹¹C-tracer was transported towards the root and distributed uniformly in the lower internodes along the pathway.