Evaluation of white radish sprouts growth influenced by magnetic fields using TOF-SIMS and MCR

Time-of-flight secondary ion mass spectrometry (TOF-SIMS) is powerful for providing chemical and spatial information. It is, however, often difficult to interpret TOF-SIMS data of complex samples such as tissues because of peak overlapping and unpredictable fragmentation of biomolecules, and therefore, data analysis techniques have been required to interpret TOF-SIMS data. In this study, multivariate curve resolution (MCR), extracting pure component spectra from original data containing mixed information of all materials in a sample, was applied to TOF-SIMS data of white radish sprouts to investigate physiological phenomena in the plant by comparing materials in the roots under different conditions in terms of magnetic fields. Influence of magnetic fields on plant growth was reported, but the mechanism has not been clarified. The sliced root samples were measured with TOF-SIMS using Au+, and then, the TOF-SIMS data were analyzed using MCR. As a result, the tissue area was distinguished from the others such as the substrate and compounds used for sample preparation by means of MCR, and the spectra of the components related to the tissue were obtained. Secondary ions specific to the sample, under a particular condition of magnetic fields, were suggested by analyzing the spectra of the tissue-related components. It is indicated that it is useful to apply MCR into TOF-SIMS spectra and secondary ion images to extract less complex spectra from intricate tissue samples. Copyright © 2012 John Wiley & Sons, Ltd.