Developing fluorescence hyperspectral imaging methods for non-invasive detection of herbicide safeners action mechanism and effectiveness

Herbicide safeners are considered key agents for plant protection that reduce the harmful impacts of herbicides on crops and the environment in general, but traditional evaluation methods for their effectiveness are time-consuming and labor-intensive. In this study, a rapid and non-destructive method was proposed using chlorophyll fluorescence and hyperspectral imaging that combined with machine learning models. Besides, chemometric analysis was utilized to reveal the action mechanism between the wheat crop (Triticum aestivum L.) understudy and the herbicide isoproturon (ISO) and safener gibberellin acid (GA₃). The results showed that ISO caused oxidative stress and disrupted the photosynthesis mechanism in wheat by hindering the electron transport pathway from primary acceptor quinone to secondary acceptor. Meanwhile, GA₃ stimulated wheat to synthesize more glutathione (GSH) that accelerated the herbicide action metabolism. It's worth noting that excessive GA₃ has decreased significantly the GSH and photosynthetic pigment concentrations, while the malondialdehyde concentration was significantly (p < 0.05) increased. Additionally, competitive adaptive reweighted sampling proved the best performance when combined with partial least squares regression for predicting the phytochemical concentrations that characterized the effectiveness of GA₃. In conclusion, the novelty of the current study came from the accurate real-time tracking method for GA₃ action mechanism and its effectiveness on ISO toxicity. Where, that model holds great value for reducing the traditional methods' limitations in safener developments.