Hydrogen Peroxide Measurement Can Be Used to Monitor Plant Oxidative Stress Rapidly Using Modified Ferrous Oxidation Xylenol Orange and Titanium Sulfate Assay Correlation

Various methodologies, sensitivities, and types of interference affect the quantification of plant hydrogen peroxide (H2O2) concentration. Modified ferrous oxidation xylenol orange (eFOX) assay and titanium sulfate (Ti(SO4)2 assay are relatively accessible methods. However, their correlation is unknown, for example whether we can get the same results for different species in different environments. Leaf samples of Ambrosia trifida, Solidago altissima, Artemisia princeps, and Sicyos angulatus were collected from a riparian vegetation zone on sunny days. The H2O2 concentration in the plant leaves was evaluated in two groups. Nonfrozen leaf samples were prepared for analysis soon after arriving at the laboratory, and frozen leaf samples were stored at −80 °C for 25 days and prepared afterwards. The eFOX assay can measure even lower fluctuations in H2O2 concentration than the Ti(SO4)2 assay. A substantial correlation was observed between nonfrozen and frozen samples in the eFOX (r = 0.879, p < 0.001) and Ti(SO4)2 assays (r = 0.837, p < 0.001). Sample weight did not affect H2O2 quantification. Each species showed a substantial correlation between the eFOX and Ti(SO4)2 assays in nonfrozen conditions (Ambrosia trifida (r = 0.767, p < 0.001), Solidago altissima (r = 0.583, p < 0.001), Artemisia princeps (r = 0.672, p < 0.001), and Sicyos angulatus (r = 0.828, p < 0.001)). Therefore, both methods can be utilized easily and rapidly to quantify oxidative stress using H2O2.