Application of Enriched Stable Isotopes in Element Uptake and Translocation in Plant

Isotope technique including radioisotopes and stable isotopes is useful and potent tool for various scientific areas. Especially, enriched stable isotopes are indispensable tools for researchers in biological systems (Stürup et al. 2008). Stable isotope ratios are usually used in examining the biogeochemical cycling of light elements such as carbon(C), oxygen (O), nitrogen (N) and sulphur (S) in the environment. Thermal ionization mass spectrometry (TIMS) for the isotope analysis has been the most standard technique for many years. However, for TIMS analysis, time for sample preparation is needed because sample need to ensure efficient ionization. On the other hand, ICP-MS analysis has some advantages that sample preparation is simple and high sample throughput for isotope experiments where a large amount of samples need to be analyzed (Stürup et al. 2008). The disadvantage to resolve in isotope analysis using ICP-MS is spectroscopic interferences in the process of analysis. It is therefore needed to be resolved these interferences. When plant physiologists investigate mineral absorption mechanisms in roots of plant, evaluation of symplastic mineral absorption capacity in roots cell in kinetics and time course experiments is very important because mineral translocation in shoots is mainly contributed to capacity of symplastic absorption in roots. In these experiments, radioisotopes methods are mainly used for element uptake in plants. Radioisotopes in solute were the most useful markers used in nutrient uptake and translocation in plants because they are chemically similar to the solute and can be distinguished from non-labeled solutes already contained in the roots (Davenport 2007). However, there are limitations to this method, including radioisotope administrative restriction and the restricted half-life of the radioisotope. Isotope tracer experiments, using a stable isotope, are very similar to those using a radioisotope on element to analyse plant mechanisms (Stürup et al. 2008). Accurate and precise determination of mineral isotope ratios is required for analysis of enriched stable isotopes. Inductive coupled plasma mass spectrometry (ICP-MS) has now become the effective and potent technique for enriched stable isotope tracer experiments due to increased availability. Therefore, the application of enriched stable isotopes in various biological systems increased rapidly.