ABSTRACT
Objective:To explore the composition characteristics of rhizosphere soil under <italic>Rehmannia glutinosa-Zea mays</italic> intercropping model，and screen out special signal substances in rhizosphere soil of <italic>R. glutinosa</italic> under intercropping <italic>Z. mays</italic>， so as to provide the basis for the study of allelopathic substances in continuous cropping obstacle of <italic>R. glutinosa</italic>. Method:In this experiment，rhizosphere soils of <italic>R. glutinosa</italic> under <italic>Z. mays </italic>intercropping and <italic>R. glutinosa </italic>single cropping models in July，August，September and October were taken as the research objects， and the volatile organic compounds in ethyl acetate fraction were analyzed by gas chromatography-mass spectrometry （GC-MS）. Principal component analysis （PCA）， hierachical cluster analysis （HCA） and orthogonal partial least squares discriminant analysis （OPLS-DA） analysis were performed on the data by SIMCA 14.1 to screen out potential differences in volatile organic compounds between the two models. Result:The types of volatile organic compounds in intercropping and single cropping models were mainly hydrocarbons， alcohols， esters， ketones， amides， acids and other substances. Specifically， the average relative contents of hydrocarbons，esters and amides in intercropping model were 58.46%，32.15% and 5.42% respectively，while the relative contents of hydrocarbons，esters and amides in single cropping model were 37.27%，36.11% and 21.13%. The results of PCA and HCA showed that the characteristics of volatile organic compounds in the ethyl acetate fraction of rhizosphere soil under intercropping and single cropping models could be clearly divided into two categories，the screening results of potential differential components based on OPLS-DA analysis indicated that various components， such as dibutyl phthalate，（<italic>Z</italic>）-9-oleamide，<italic>β</italic>-caryophyllene，dioctyl iso-phthalate， phthalate （2-propylamyl） diester， <italic>n</italic>-hexadecane，octodecane， <italic>n</italic>-heneicosane， were screened from rhizosphere soil under the two models. Conclusion:The <italic>R. glutinosa-Z. mays</italic> intercropping model has certain effects on the volatile organic compounds in the rhizosphere soil of <italic>R. glutinosa</italic>，and the effect of the selected components on the growth and quality characteristics of <italic>R. glutinosa</italic> still need to be further studied.
ABSTRACT
Objective: To discuss the phenotypic character and the HPLC fingerprints of radial striations from different germplasms Rehmanniae Radix. Method: The changes in the shape and column diameter of the radial striations of Rehmanniae Radix were observed and measured in the whole growth period. Besides,the HPLC fingerprints of the root,radial and un-radial striations were established to sign the chemical quality and analyzed by principal component analysis(PCA)and systematic cluster analysis. Result: There were significantly differences and regularities in the shape and proportion of the radial striations of different germplasms Rehmanniae Radix. The fingerprints showed the consistency between different types of chemical ingredients,and the differences in chemical quality characteristics mainly lay in the content of chemical compositions and theirs relative ratio. The results of PCA indicated that active ingredients, such as acteoside,catalpol,rehmaionoside D,rehmaionoside A and leonuride, were involved in the quality expression of different parts from various germplasms of Rehmanniae Radix,but each ingredient had a distinctive contribution rate to the differential quality expression between different parts from various germplasms of Rehmanniae Radix. However,the other components involved in the differential quality expression had different contribution rates in different germplasms.The systematic cluster analysis indicated that great differences in the chemical quality between the radial striations and un-radial striations of Beijing-1,Qinhuai,Qinhuai Zheng and 1706 germplasms,but with small differences in 85-5 and Baixuan germplasms. Conclusion: There are differences in phenotypic character of the radial striations and HPLC fingerprints between different germplasms Rehmanniae Radix.