ABSTRACT
ObjectiveTo establish a simple， fast and accurate method for locating the volatile oil in Angelicae Sinensis Radix based on frozen section and fluorescence imaging technology， and to reveal the distribution and accumulation of volatile oil in the roots of this herbal medicine. MethodAngelicae Sinensis Radix was used as the research material， the best frozen section conditions for the research material were established by comparing the effects of different cryoprotectants on the quality of frozen sections of Angelicae Sinensis Radix. The suitability of Sudan Ⅲ chemical staining and fluorescence localization for positioning the volatile oil were compared according to the loss of volatile oil and the complexity of operation process. ResultA new method for evaluating the quality of frozen sections of Angelicae Sinensis Radix was established. According to the evaluation equation， it was found that the highest score was obtained when the head， body and tail positions of Angelicae Sinensis Radix were treated with 20% glycerol， 15% glycerol and 20% sucrose， respectively. There was yellowish-brown oily substance in the oil chambers of phelloderm and secondary phloem， and oil canal of the secondary xylem of Angelicae Sinensis Radix， which could be stained orange red or orange yellow by Sudan Ⅲ， and there was green spontaneous fluorescence in the same part under the fluorescence microscope. ConclusionThe relatively complete section of Angelicae Sinensis Radix can be obtained after being treated with cryoprotectant. The volatile oil exists in the oil chambers of phelloderm and secondary phloem， and oil canal of the secondary xylem of Angelicae Sinensis Radix. This study can provide reference for observation of the accumulation sites of volatile oil in other plants.