SEM Observation of Wet Lily Pollen Grains Pretreated with Ionic Liquid

Abstract

Mature pollen grains of Lilium cultivar, with their germ pores folded in upon themselves, were observed under a scanning electron microscope (SEM). The conventional pretreatment process requires aldehyde fixation, dehydration, drying and metal sputtering for SEM observation. These complicated and laborious procedures can considerably alter the morphology of pollen grains. In order to omit this conventional pretreatment process, we established a novel technique utilizing an ionic liquid (IL) that is composed solely of ions, namely, a liquid salt that can remain in a molten state even at room temperature. IL-treated pollen grains could be observed under vacuum conditions without artifacts, and furthermore, a satisfactory SEM image could visualize pollen grains in a wet state. The possible direction of future studies on ionic liquids in the SEM field is also discussed.