[Effect of different nitrogen forms and concentrations on biomass and alkaloids of isatidis folium]

In order to provide theoretical basis of improving nitrogen utilization efficiency in Isatis indigotica, the biomass and active components in Isatidis Folium under different nitrogen forms and concentrations were analyzed.

I. indigotica was cultivated by sand culture in greenhouse, and the experiment was designed with orthogonal test L25 (5(6)). As an index to the biomass and indigo, indirubin, the effects on the I. indigotica by three factors [NO3(-) -N, NH4(+) -N, CO(NH2)2] at five different levels were studied.

There were significant difference of the biomass and active components by different nitrogen forms and concentrations. The effect of amide nitrogen [CO(NH2)2] on biomass of Isatidis Folium was the most apparent, and the effect of ammonium nitrogen on indirubin was more obvious. Considering the biomass and active ingredient, one combination was optimized, which was (NH4)2SO(4)-7.5 mmol x L(-1), KNO(3)-2.5 mmol x L(-1), CO(NH2)(2)- 5 mmol x L(-1).

It is important to promote the growth in pre-stage of I. indigotica, and cost-effective combination of balanced nitrogen fertilizer could reasonably promote the growth, and improve the contents of active components and individual biomass.