Research Examines Far-Red Photons' Impact on Tomato Photosynthesis

Study finds inclusion of far-red photons essential for accurate estimation of light compensation point in tomato plants.

Published on Mar. 6, 2026

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New research from the University of Connecticut and The Ohio State University examines how different ratios of far-red to photosynthetically active radiation (PAR) impact the light compensation point (LCP) in tomato plants. The findings highlight that far-red photons enhance photosynthesis in a synergetic manner with PAR photons, and that estimated LCP values differ depending on the definition of PAR used (400-700nm or 400-750nm).

Why it matters

Understanding the impact of far-red photons on photosynthesis is crucial for optimizing lighting conditions in controlled environment agriculture, such as greenhouses and vertical farms, to maximize plant growth and productivity. This research provides important insights that can inform the design of efficient lighting systems for tomato and other crop production.

The details

The study examined changes in LCP under two different far-red to ePAR (400-750nm) ratios - 2% and 44% - for both the acclimatization and light response curve measurement light sources. The results showed that the different far-red to ePAR ratios altered the LCP, indicating that far-red photons enhance photosynthesis in a synergetic manner with PAR photons. Additionally, the estimated LCP values differed depending on whether PAR (400-700nm) or ePAR (400-750nm) was used to define photosynthetically active radiation.

  • The research was published on March 6, 2026.

The players

Dr. Changhyeon Kim

Assistant professor at the University of Connecticut, formerly a postdoctoral scholar at Kubota lab at The Ohio State University. His research interests include understanding crop responses to varying environmental conditions, development of efficient management practices, and the application of new technology to maximize economic feasibility of Controlled Environment Agriculture.

Dr. Chieri Kubota

Distinguished Professor at The Ohio State University. Her projects are in an interdisciplinary area that encompasses plant physiology and horticultural engineering to enhance understanding and efficiency of CEA plant production systems such as greenhouses, warehouses (vertical farms), and growth chambers.

American Society for Horticultural Science (ASHS)

A respected and influential professional society for horticultural scientists, committed to promoting and encouraging national and international interest in scientific research and education in all branches of horticulture.

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What they’re saying

“The findings highlight that different FR-to-ePAR ratio alter LCP as FR photons enhance photosynthesis in a synergetic manner with PAR photons. In addition, estimated LCP values differed depending on the definition of photosynthetically active radiation (either PAR or ePAR). These results indicate that inclusion of FR photons is essential for accurate estimation of LCP when the light environment of interest includes FR photons.”

— Dr. Changhyeon Kim, Assistant Professor, University of Connecticut (Mirage News)

What’s next

The researchers plan to further investigate the specific mechanisms by which far-red photons interact with PAR photons to enhance photosynthesis in tomato plants, with the goal of developing more efficient lighting strategies for controlled environment agriculture.

The takeaway

This research highlights the importance of considering the impact of far-red photons when designing lighting systems for tomato and other crop production in controlled environments, as the inclusion of far-red light can significantly improve the accuracy of key photosynthetic measurements like the light compensation point.