Adding Time Dimension to Photosynthesis Studies: A Path Toward Linking Biomass to Photosynthesis

Biomass is a key indicator of growth rate, resource use efficiency, and overall plant performance. Biomass is ultimately driven by photosynthesis, as it reflects the plant's ability to convert light energy into chemical energy and build structural and storage tissues over time. In recent years, high‐throughput photosynthesis phenotyping methods have been developed using pulse‐amplitude modulated chlorophyll fluorescence. These methods allow fast whole‐plant measurements that can be taken daily and multiple times per day, offering the opportunity to capture variation in photosynthesis over time. In this study, we introduce a novel method to estimate the above‐ground dry biomass of three plant species by utilizing the daily electron integral (DEI) as a correction factor for plant‐projected areas. This new approach considers whole plant measurements of the operating efficiency of PSII, as well as time variation within the day and across the experiment. Our findings demonstrate a strong linear correlation between this new index and biomass under two light conditions, evidenced by an R 2 value of 0.98.