A new low-cost portable multispectral optical device for precise plant status assessment

Plant stress monitoring is of crucial importance to understand the plant response to environmental conditions, has been widely applied in various fields including biology, agronomy, botany, and horticulture. A number methods and instruments for plant stress monitoring have been proposed, most of which show significant such as high cost, poor accuracy or complex operation that limit the use of such devices. In this, we propose a low cost, portable active multispectral optical device for precise plant stress detection and mapping named Plant-O-Meter. The device has an integrated multispectral source that comprises light of the four most indicative wavelengths (850, 630, 535 and 465 nm), and enables simultaneous illumination the whole plant. Sequential illumination and detection provide rapid reflectance measurements, are wirelessly transmitted to android operated devices for processing and data storing. The device was in laboratory conditions comparing the Plant-O-Meter measurements with the image results from a hyperspectral camera and a GreenSeeker handheld device and under field conditions with the. The comparison revealed comparable performance, showing strong correlation with both the (R2=0. 997) and the GreenSeeker handheld (R2=0. 954 from the laboratory measurements and2=0. 886 from the field experiments), indicating that the device exhibits strong potential for accurate plant measurements. Moreover, owing to the very simple operating principle, the device represents a compact, -effective, and easy-to-operate solution.