The chromosome-level reference genome of Coptis chinensis provides insights into genomic evolution and berberine biosynthesis.

Coptis chinensis Franch, a perennial herb, is mainly distributed in southeastern China. The rhizome of C. chinensis has been used as a traditional medicine for more than 2000 years in China and many other Asian countries. The pharmacological activities of C. chinensis have been validated by research. Here, we present a de novo high-quality genome of C. chinensis with a chromosome-level genome of ~958.20 Mb, a contig N50 of 1.58 Mb, and a scaffold N50 of 4.53 Mb. We found that the relatively large genome size of C. chinensis was caused by the amplification of long terminal repeat (LTR) retrotransposons. In addition, a whole-genome duplication event in ancestral Ranunculales was discovered. Comparative genomic analysis revealed that the tyrosine decarboxylase (TYDC) and (S)-norcoclaurine synthase (NCS) genes were expanded and that the aspartate aminotransferase gene (ASP5) was positively selected in the berberine metabolic pathway. Expression level and HPLC analyses showed that the berberine content was highest in the roots of C. chinensis in the third and fourth years. The chromosome-level reference genome of C. chinensis provides important genomic data for molecular-assisted breeding and active ingredient biosynthesis.

[Study on reflectance spectra morphological character of the hyperspectral mixed pixels at different component proportion].

Under the experimental condition, the hyperspectral reflectance spectra of the mixed pixel of lotus and water body were acquired using the multi-angles dichotic reflex platform and ASD spectrum instrument. The reflectance spectral morphological character index variation of the hyperspectral mixed pixel at different component proportion was analyzed. The conclusions are as follows: the correlation between these morphological indexes was obvious, and the best morphological index was chosen by removing the index whose R2 was greater than 0.5 (R is correlation coefficient); the variation of different morphological index was obvious; the cluster analysis shows that there was a critical value in the progress of the transformation from the pure pixel (water) to mixed pixel. If the proportion was less than the critical value, the reflectance spectra reflected the reflection characteristics of pure pixel; otherwise, it was the reflection of characteristics of mixed pixel.

[Study on the nonlinear characteristics of the mixed pixel's reflectance in hyperspectral space].

Under the experimental condition of the 50 degree incidence zenith angle and 45 degree detection azimuth, 24 groups of reflectance spectral of the mixed pixel of lotus and water body acquired using the reflex platform and FieldSpec 3 Hi-Res portable spectrum instrument. The hyperspectral space was built based on the reflectance character. The relationship between similarity and the index of lotus area ratio was analyzed using the linear, logarithm and quadratic curve fitting, and the goodness of fitting is 63.6%, 76.2% and 82.9% respectively. According to the real relationship of the mixed pixel spectral vector and the reference spectral, the best fitting model has nonlinear characteristics. The idea that the mixed pixel may have the critical value was proposed on the base of the analysis. The research result will help understand the mixed pixel further, and provide a new direction for unmixing the mixed pixel.

[Analysis of the polarization properties of snow in a different melting state].

Nowdays, under the circumstance of global warming, the traditional study of solid-state snow can not meet the current needs. The present paper involves qualitative analysis of the polarization reflectance spectrum of snow in a different melting state. Special attention is paid to the investigation of the relationship among polarization angles, azimuth angles, the light incidence zenith angles, the detection zenith angles and the different types of snowmelt. It turns out that all these factors have certain influences on the polarization reflectance spectrum of different types of snowmelt. At the waveband of the visible light, the polarization reflectance of snowmelt is the largest at 90 degrees, and the smallest at 0 degrees. The wider the detection angles and the incidence angles, the larger the polarization reflectance. Anomalies (unusual phenomena), different from other spectra, occur when the polarization reflectance spectrum of snowmelt is observed at different azimuth angles. The characteristics of polarization spectra at some certain wavebands play an important role in determining the water content of snowmelt, and meanwhile with the increase of which, the polarization reflectance will go down obviously. These rules have laid a solid foundation for the quantitative analysis of snowmelt properties by using polarization spectrum in the future and are also of great importance in fresh water management as well as monitoring natural disasters such as the spring flood.

[Studies of the thermal radiation multi-angle polarization properties of snow].

This paper, catering to the need of the study of remote sensing for thermal radiation polarization properties of ground features, detects the thermal radiation multi-angle polarization properties of snow, and makes analysis of effects of four factors, i. e. detecting zenith angle, detecting azimuth angle, bands and polarizing angle, on the thermal radiation properties of snow. The results show that the radiance and brightness temperature of snow increases with the detecting zenith angle. When the detecting zenith angle is greater than 30 degrees, the growth accelerated, and the effect of detecting zenith angle on the brightness temperature of snow is more significant than that of the radiance; the changes in detecting azimuth angle have some effect on the radiance and brightness temperature of snow, and have much influence on the brightness temperature than that of the radiance; the radiance and brightness temperature of snow is significantly affected by the changes in bands, and the effect on the radiance is more significant; the changes in polarizing angle have some effect on the radiance and brightness temperature of the snow, and have much influence on its brightness temperature. The results of the study provide new ideas and methods for the application of remote sensing technology to carrying out the thermal infrared quantitative study of snow, and have important theoretical significance and potential applications.

[Studies of the thermal radiation characteristics of urban typical surface features].

The use of thermal infrared technology to monitor the land surface temperature has received mature development, and the acceleration of urbanization makes the urban heat effect emerge, thus, studies of the thermal radiation characteristics of urban typical surface features make great significance for the analysis of the causes and distribution of the thermal phenomenon. Based on the study of ground measured data of Baoding city, we have found that, the feature types, the observation time and wall orientations are principal factors that exert an influence on the thermal radiation brightness temperature of urban typical surface features. The results show that different types of surface features will significantly affect the brightness temperature, but "different things with the same spectrum" still exists; the observation time has direct impact on the intensity of thermal radiation and to a large extent on the brightness temperature difference of each channel; the brightness temperature of different wall orientations are also different, and the difference changes with the change in observation time. Studies of thermal radiation characteristics of urban typical surface features have theoretical and practical significance, providing basis for thermal infrared remote sensing to monitor the urban heat effect.

[Study on the reflected and hyperspectral mixed-pixel character of aquatic plants and water].

A study on the reflected and hyperspectral mixed-pixel of aquatic plants and water was given by using a orthogonal experimental design with three factors and two levels. The results of F test suggest that for the single factors, the band and the area ratio of mixed-pixel on the reflected and hyperspectral mixed-pixel of the reflection effects are particularly significant, however, the detector angle had no significant effect under these experimental conditions; For the interaction, the band and the area ratio of mixed-pixel, the detector and the area ratio of mixed-pixel, the effects of these two interactions on the reflected and hyperspectral mixed-pixel are also particularly significant, This study did quantitative analysis of the factors affecting the reflected and hyperspectral mixed-pixel character and their interaction, and provided a new method for the indepth study of mixed-pixel.