ESEM imaging of dynamic biological processes: the closure of stomatal pores

Historically, electron microscopy of dynamic biological processes has been impossible to achieve in real time because conventional electron microscopy requires specimen fixation, dehydration and metallic coating. The advent of the environmental scanning electron microscope removes these restrictions, allowing fully hydrated samples to be imaged in their native state. We explore the possibility of secondary electron imaging of biological systems undergoing natural morphological changes in the microscope chamber and present a proof of principle study on the closure of stomatal pores in Tradescantia andersonia leaf tissue. An imaging protocol is developed and the advantages and limitations of this high-resolution imaging technique are considered, including a discussion of potential beam damage mechanisms.