Development of a 14C detectable real-time radioisotope imaging system for plants under intermittent light environment

A new real-time radioisotope imaging system (RRIS) to study the kinetics of nutrient uptake and transfer of photosynthetic products in a living plant was developed and evaluated through a test run. 14C is a common radioisotope of carbon and useful to trace the photosynthetic products as well as a low energy beta emitter. The rationale of this study was to develop a RRIS that has the ability to detect low energy beta emitters, such as 14C, 35S, and 45Ca. To achieve compatibility between the detection of low energy beta emitters and irradiation of the test plant, an intermittent lighting system was added to the RRIS. Furthermore, a commercially available digital camera was added to the RRIS for acquisition of photographic images of the test plants. The capabilities of the new RRIS were evaluated through a test run by using seedlings of rice plants and 35S-labeled sulfate. It was shown that the new RRIS was able to detect 35S absorbed by rice plant seedlings, and it was able to acquire photon-counting images and photographic images of the test plants simultaneously. Despite some limitations, the new RRIS provides a means to study the kinetics of elements in plants by utilizing low energy beta emitters. (author)