Related Experiment Video
Updated: Jul 18, 2026

Luminescence Lifetime Imaging of O2 with a Frequency-Domain-Based Camera System
Published on: December 16, 2019
Effects of light intensity and water temperature on oxygen release from roots into water lettuce rhizosphere
1Division of Sustainable Energy and Environmental Engineering, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan. soda@see.eng.osaka-u.ac.jp
Abstract:
The oxygen release rate into the rhizosphere by a floating aquatic plant-water lettuce-was determined under various light intensities (0.0-1.2x10(5)lx) and water temperatures (10-35 degrees C). The net specific oxygen release rate was expressed by a model equation comprising the gross oxygen release rate and the rhizosphere respiration terms. Experimental and simulated results show that the net specific oxygen release rate increased with light intensity up to the optimal value, but slight inhibition by higher light intensities was observed at 10-20 degrees C. With increased water temperature, the respiration rate became larger than the gross oxygen release rate. The maximum net specific oxygen release rate of 11.0-12.5mg-O(2)kg-wet(-1)h(-1) was obtained at the optimal condition of about 25 degrees C and 9.0x10(4)-1.1x10(5)lx. The net oxygen release rate was negligible at 35 degrees C at any light intensity because the respiration rate was much greater than the gross oxygen release rate into the rhizosphere.
Related Concept Videos
Freshwater Microbial Ecology
Oxygen Requirements and Growth Patterns
Microenvironments
Marine Microbial Ecology
Responses to Drought and Flooding
Microbes and Climate Change

