Postharvest imaging of chlorophyll fluorescence from lemons can be used to predict fruit quality

We demonstrate the feasibility of assaying and predicting post-harvest damage in lemons by monitoring chlorophyll (Chl) fluorescence. Fruit quality was assayed using a commercial instrument that determines photosynthetic performance by imaging Chi fluorescence parameters under different irradiances. Images of Chi fluorescence from individual lemons reveal that photosynthesis is active throughout the post-harvest ripening process. Because photosynthesis is highly sensitive to biotic and abiotic stress, variations in Chi fluorescence parameters over the surface of a lemon fruit can be used to predict areas that will eventually exhibit visible damage. The technique is able to distinguish between mould-infected areas that eventually spread over the surface of the fruit, and damaged areas that do not increase in size during ripening. This study demonstrates the potential for using rapid imaging of Chi fluorescence in post-harvest fruit to develop an automated device that can identify and remove poor quality fruit long before visible damage appears.