摘要：Many plants, including fruits and vegetables, release biogenic gases containing various volatile organic compounds such as ethylene (C
2H
4), which is a gaseous phytohormone. Non-destructive and in-situ gas sampling technology to detect trace C
2H
4 released from plants in real time would be attractive for visualising the ageing, ripening, and defence reactions of plants. In this study, we developed a C
2H
4 detection system with a detection limit of 0.8 ppb (3σ) using laser absorption spectroscopy. The C
2H
4 detection system consists of a mid-infrared quantum cascade laser oscillated at 10.5 µm, a multi-pass gas cell, a mid-IR photodetector, and a gas sampling system. Using non-destructive and in-situ gas sampling, while maintaining the internal pressure of the multi-pass gas cell at low pressure, the change in trace C
2H
4 concentration released from apples (
Malus domestica Borkh.) can be observed in real time. We succeeded in observing C
2H
4 concentration changes with a time resolution of 1 s, while changing the atmospheric gas and surface temperature of apples from the ‘Fuji’ cultivar. This technique allows the visualisation of detailed C
2H
4 dynamics in plant environmental response, which may be promising for further progress in plant physiology, agriculture, and food science.
