Forecast of citrus leaves frozen injury based on spectral signature

Electrical conductivity is an important physiological and biochemical index which reflects the situation of plant biomembrane system and also reflects the nutrient condition of trees. The nutrition of the tree before winter is an important factor which resists extreme low temperature for surviving through the winter, the exudation or degradation of cell sap is an index of freezing degree when freezing injury happened. The research was to scan the different leaves in different freezing levels with a spectrometer, and the stepwise regression method was used to analyze the relation between spectral reflectivity and leaf conductivity, and then constructing the leaf conductivity and spectral reflection model. The results showed that there was a close relationship between citrus leaf electrical conductivity and spectral reflectance, the errors of predicted values by the two models were both less than 10% compared to measured values, which proved the two models had good predicted accuracy. The results can provide a reference for remote sensing to monitor the growth status and cold injury situation of orchards.