[Research on spectral reflectance characteristics for Glycyrrhizae Radix]

In order to study the spectral reflectance differences of Glycyrrhizae Radix under different growth conditions and lay the foundation for quantitative monitoring of Glycyrrhizae Radix remote sensing images, spectra of Glycyrrhiza species under different growth period and different varieties and different regions were measured by a portable spectrometer. The results showed that the reflectivity of annual G. uralensis was obviously higher than that of the two years plant in the visible light band own to the contents of crown layer chlorophyll. The reflectivity of two years G. pallidiflora was higher than that of G. uralensis in the near infrared band own to the leaf area index and the content of leaf water. The red edge spectrum of annual plant fluctuated largely than that of two years plant due to vegetation coverage and leaf area index. G. pallidiflora grew well than G. uralensis. Under different regions of the Glycyrrhiza species, spectral data analysis showed that within a certain range, the average annual precipitation and average annual evaporation were the major factors to affect the differences of Glycyrrhiza species spectral data under different regions owe to the leaf water content, the higher leaf water content, the lower spectral reflectance. The principal component analysis and continuum-removed method of the spectral data under different regions found that, within a certain range, the average annual precipitation and average annual evaporation were the major factors caused by the differences of Glycyrrhiza species spectral data under the different regions, Glycyrrhiza species spectral similarity related to the spatial distance.