Assessment of Carbon Allocation with Stable Carbon Isotope Labeling

Abstract

Abstract Labeling plants with isotopic forms of C allows many processes important to agriculture and/or natural resource management to be studied. Most C‐labelling experiments have employed radioactive 14 C, but in recent years regulatory constraints associated with use of radioactive materials appear to have curtailed studies which may have benefited from 14 C labeling. In this paper, we describe a procedure for using the stable isotope 13 C for C labelling. By using gas‐isotope‐ratio mass spectrometry, isotopic differences as small as 0.4 µg of 13 C could be detected in the 23‐d‐old cheatgrass ( Bromus tectorum L.) we used to demonstrate the technique. The procedure is flexible and can be applied to most plant species and a wide range of research objectives. Because 13 C is a naturally occurring stable isotope, there are no regulatory problems, environmental hazards, or health risks associated with its use.