Work

Plant stress detection through a chlorophyll content-dependent relationship between Fv/Fm and the photochemical reflectance index

Year: 2026

Type: article

Abstract: Optical sensing for plant stress detection requires physiologically relevant indices. Fv/Fm, representing the maximum quantum yield of photosystem II photochemistry, quantifies stress across species but requires dark adaptation, limiting field application. Photochemical reflectance index (PRI), a reflectance-based indicator of xanthophyll cycle activity, can be remotely measured, but its irregular variation complicates interpretation. Paddy rice was grown in temperature-gradient field chambers to evaluate Fv/Fm, PRI, and SPAD (soil-plant analysis development). Changes in Fv/Fm were associated with net leaf photosynthesis and showed sensitivity to stress affecting PSII, as its maximum value decreased under high-temperature stress. PRI exhibited a diurnal pattern similar to that of Fv/Fm, while the linear PRI-Fv/Fm relationship varied with SPAD values throughout the season. Utilizing this relationship, variation in Fv/Fm can be inferred from PRI and chlorophyll content, enabling spatial and temporal scaling and quantitative stress assessment. These findings support remote sensing-based plant stress diagnosis.

Source: Photosynthetica

DOI: 10.32615/ps.2026.028