Optimised spectrophotometric determination of anthocyanins in wheat leaves: a modified Sims and Gamon (2002) method

Abstract

The widely used Sims and Gamon (2002) spectrophotometric formula for leaf anthocyanin estimation frequently produces negative values when applied to wheat (Triticum aestivum L.), because its chlorophyll-correction coefficient (0.288) was calibrated on broadleaf species and overcorrects in monocots with low anthocyanin and high chlorophyll. Using paired absorbance and chlorophyll data from winter wheat across three seasons (2022, 2024, 2025; n = 700, 18 cultivars, three nitrogen treatments), we derive a wheat-specific coefficient (k = 0.215) and add a 750 nm baseline correction. The optimised formula reduces physically implausible negative values from 49% to 26% and yields concentrations consistent with published cereal ranges. No additional reagents or measurements are needed, and the correction can be applied retrospectively to existing absorbance datasets.We recalibrate the chlorophyll-correction coefficient for wheat using a zero-anthocyanin constraint on high-chlorophyll leaves.Adding a 750 nm baseline correction accounts for scattering and turbidity absent from the original formula.The method is validated across three seasons, 18 cultivars, and three nitrogen levels with consistent results.

Xiaoxin Song

PhD Student

My research interests include multi-scale plant and crop phenotyping, crop growth and senescence monitoring, dynamic modelling, and remote sensing.

Prof. Dr. Kang Yu

Professor of Precision Agriculture

My research interests include precision crop farming, hyperspectral remote sensing, and AI in agriculture.