2020 Small World in Motion Competition

Herb (Tradescantia spathacea) leaf stoma (breathing pore) responding to CO2 and RH transients

Dr. Douglas Clark

Paedia Corporation
San Francisco, California, USA

Brightfield, Image Stacking

50X (Objective Lens Magnification)

Dr. Clark, who works in engineering and scientific consulting, created this video of an herb leaf stoma (Tradescantia spathacea) responding to transient changes in CO2 levels and relative humidity (RH). This movie is actually a time-lapse spanning 250 minutes condensed down to 10 seconds. A sealed environmental chamber was built around the microscope in order to administer different light, temperatures, and gas concentrations to observe reactions of the subject. The live leaf stoma is shown breathing, with the various reactions stimulated by changes in CO2 mixes and RH. The images were processed using focus stacking in order to keep the entire image in focus, and morphing software to smooth frame to frame transitions. Koehler illumination was used.