Scientists have advanced methods to make maps of the locations of molecules within plant materials. Resolution of 10 to 50 microns, less than a quarter the size of a human hair, is routinely possible. The trick with plant materials is to extract the molecules delicately from thin slices with a fine laser moving stepwise across the sample.Many molecules are analyzed at once using a very sensitive mass spectrometer in this technique known as matrix-assisted laser deposition/ionization-mass spectrometry imaging (MALDI-MS). Within cottonseed embryos, which are about 3/16th of an inch in diameter, this method showed a surprisingly non-uniform mixture of lipids whose concentration varies with tissue functionality. These lipids are important for seed development and can affect the chemistry of the cottonseed oil extracted for use in various foods.These findings demonstrate the potential of this technique to provide a new level of understanding of biosynthetic pathways.
Spatial Mapping of Lipids at Cellular Resolution in Embryos of Cotton