Measuring Dynamical Responses of Plants to Global Change Using Short-lived Radioisotopes

Calvin Howell, Duke University

A collaboration of biologists and physicists at Duke University are developing a system for making non-destructive in-vivo measurements of photosynthate and nitrogen translocation in plants under precisely controlled environmental conditions. A goal of this work is to build a research infrastructure for studying the dynamical responses of plants to global change, in particular the increasing concentration of atmospheric CO2.

The Radioisotope Tracing with Environmental Controls (RTEC) system is based on the use of short-lived radioisotopes and gamma-ray coincidence counting techniques. The system utilizes two facilities at Duke University: the Phytotron and the Triangle Universities Nuclear Laboratory (TUNL). The substance tracing measurements are made in an environmentally controlled growing chamber at the Phytotron, and the short-lived isotopes are produced in substances using the tandem Van de Graaff accelerator at TUNL which is located less than 100 m from the Phytotron. Examples of radioisotope-tagged compounds used in the initial research program include 11C tagged photosynthates, 13N tagged nutrients, and 15O and 18F tagged water. Details of the experimental techniques, examples of current RTEC studies, and some preliminary results will be presented.

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