Chlorophyll Fluorescence-Based Plant Health Monitor

This project concerns the development of a sensor intended to remotely monitor plant stress using active stimulation of plant chlorophyll fluorescence. The intensity and spectral band shape of leaf chlorophyll fluorescence in green plants has been linked to the physiological status of the plants and thus provides a good indicator of plant health. The proposed sensor will measure the relative intensity of plant fluorescence in two wavelength bands corresponding to emission from Photosystems I and II. The compact size (1000 cm3), light weight (3 kg) and low power consumption (15 watts) of the sensor make this instrument ideal for robotic operation in confined spaces such as might be found on manned space missions or on ground-based facilities such as Bio-PLEX. Use of a novel active fluorescence stimulation source and compact detector enables the device to remotely sense plant fluorescence (at the single leaf, whole plant, or canopy level) from a distance of at least several feet without using a large, high power laser and large focusing optics. With the use of a synchronous detection scheme, the sensor can also efficiently detect the fluorescence in the presence of either solar or artificial lighting.