Localization of Flavonoids in Seeds by Cluster Time-of-Flight Secondary Ion Mass Spectrometry Imaging

摘要

Time-of-flight secondary ion mass spectrometry imagingnhas been used to map flavonoids in fresh seed sectionsnof peas (Pisum sativum) and Arabidopsis thaliana. Whilenfor peas a very simple preparation method derived fromnmammalian tissue imaging could be utilized, severalnpreparation methods had to be tested for the A. thaliananseeds before obtaining tissue sections on which thendiagnostic ions were not delocalized. For such small andnstiff biological material, none of the methods currentlynused in histology or scanning electron microscopy couldnbe transferred to mass spectrometry imaging. Only thenembedding of the fresh seeds in a polyester resin, followednby the analysis of the block after having obtained a flatnsurface section with a diamond blade, gave sensitive andnreproducible results. Several flavonoid ions have beenndetected in the sections, showing increased concentrationsnof flavonoids in the seed coats. The method wasnfinally applied to confirm the variations in the flavonoidncontent of seeds from different A. thaliana mutants.