Tracking Water Limitation in Photosynthesis with Sun-Induced Chlorophyll Fluorescence

Sun-induced chlorophyll fluorescence has a mechanistic link to photosynthesis. It is therefore sensitive to subtle, stress-induced changes in photosynthetic activity. This study shows the evolution of the emission of sun-induced chlorophyll fluorescence (SIF) by a yellow mustard stand grown in plant boxes under varying water supply and under varying meteorological conditions, causing changes in the evaporative demand. Affected by both leaf biochemical processes and by changes in the plant canopy structure, we combined the fluorescence measurements with reflectance measurements to assess the effect of both components. A first result of this study shows that the biochemical component of the fluorescence emission decreases because of either a reduction in the water supply or an increase in the evaporative demand by the atmosphere.