Optical spectroscopy for assessing the physiological status of plants: some examples

Abstract

A miniature system of near infrared spectroscopy (NIRS) was developed by Cemagref for measuring the maturity of fruits in the field, shaped as a glove. It could be shown that some spectral bands were more sensitive than others to the variation of temperature of the fruit. For making the calibration more robust, it proved to be helpful, said in mathematical terms, to process spectral data in an orthogonal way to the sub-space of the sensitive spectral bands. Beyond this example, Cemagref evaluates the potential of SPIR technology to assess some plant physiological parameters, especially their hydric status. First results obtained with grapevine confirm bibliographic data and suggest that this application is feasible.