[Effect of P and K Fertilization on Four Iridoids in Axial and Lateral Root of Gentiana crassicaulis].

To study the effect of phosphorus( P) and potassium( K) fertilization on four iridoids in axial and lateral root of Gentiana crassicaulis.

Field experiment was conducted based on phosphorus and potassium,and the content of four iridoids was analyzed in the axial and lateral root of Gentiana crassicaulis.

Despite of different proportion of phosphorus and potassium,the content of four iridoids in axial root was always higher than that in the lateral root, and under normal fertilizer condition, the content of axial and lateral root was 12. 36% and 9. 84%, respectively. On the condition of phosphorus and potassium fertilization, the content of gentiopicroside and loganic acid were higher than that of the swertiamarin and sweroside both in the axial and lateral root. And the difference of the two parts could be increased by high potassium with appropriate phosphorus application.

The four iridoids were more likely to accumulate in the axial root of Gentiana crassicaulis, and phosphorus and potassium fertilization, only affected the different degrees on the content of ingredients among two parts. Thus, more attention should be paid to the use of phosphorus and potassium fertilization, and the difference of the active ingredient content in the axial and lateral root of Gentiana crassicaulis.