High-Resolution Imaging of Plant Delayed Luminescence

TL;DR

This paper presents a high-resolution imaging system for plant delayed luminescence, revealing spatial heterogeneity, species-specific responses, and developing a quantum model linking DL to excited electrons, advancing plant phenotyping and photophysical understanding.

Contribution

We developed a megapixel-resolution DL imaging system and a quantum model, enabling detailed analysis of plant photophysical responses and heterogeneity.

Findings

Spatial heterogeneity in DL across Arabidopsis leaves

Species-specific DL responses to oxidative stress

Light wavelength modulates DL decay kinetics

Abstract

Delayed luminescence (DL) is a quantized signal that is characteristic of photoexcited molecules entering a relaxed state. Studying DL provides critical insight into photophysical mechanisms through the analysis of specific spatiotemporal dynamics. In this study, we developed a high-sensitivity DL imaging system using a quantitative scientific complementary metal-oxide-semiconductor (qCMOS) camera and a single-photon counting resolution. By optimizing the optical architecture and signal processing algorithms together, we achieved full-field spatiotemporal DL imaging at megapixel resolution (i.e., $2304 \times 4096$ pixels). Key findings include the following: (1) we observed spatial heterogeneity in DL intensity across the leaves of Arabidopsis thaliana, with stronger signals detected in veins and at sites of mechanical injury; (2) species-specific DL responses occur in response to oxidative stress, with Hydrocotyle vulgaris and Ginkgo biloba showing enhanced central DL activity; (3) excitation using white light induced maximum DL intensity, while red and blue light differentially modulated decay kinetics. Finally, we develop a two-level quantum model that links DL dynamics to the populations of excited-state electrons, thereby developing a theoretical framework for future photophysical research. Collectively, this work establishes a theoretical and technological framework for advancing plant phenotyping under stress conditions and optimizing light environments.