%0 Journal Article %A GUAN Jiali %A WANG Gang %A ZHANG Mengrui %A CHEN Xi %A CAO Yiwen %A TANG Xiaoqing %A WANG Kangcai %T Effect of Different Nitrogen Supply Levels on the Growth of Isatis indigotica Fort. and Quality of Medicinal Materials %D 2019 %R 10.11869/j.issn.100-8551.2019.10.2077 %J Journal of Nuclear Agricultural Sciences %P 2077-2085 %V 33 %N 10 %X A pot experiment was carried out to explore the effect of different nitrogen levels on the growth of I. indigotica and quality of medicinal materials. The response of the biomass accumulation, the photosynthetic parameters, the contents of soluble sugar, free amino acid, nitrate nitrogen and main active components of I. indigotica under 0(N0), 2.5 (N1), 5.0 (N2), 10.0 (N3), 15.0 mmol·L-1(CK) nitrogen levels were investigated. The results showed that dry weights of leaves and roots increased with the increase of nitrogen concentration, and the root-shoot ratios increased initially and then decreased. The content of soluble sugar in leaves showed a trend of decreasing initially and then increasing with the increase of nitrogen concentration. The soluble sugar content in roots showed the different trend as that in leaves. In the nitrogen concentration range of 2.5~15.0 mmol·L-1, the soluble sugar content in roots increased initially and then decreased. The contents of free amino acid in roots and leaves increased initially and then decreased with increasing of nitrogen concentration. The free amino acid content under N3 treatment was the highest. The nitrate nitrogen contents in roots and leaves showed a trend of decreasing initially and then increasing. The nitrate nitrogen content under N3 treatment was significantly lower than that of the other treatments. The net photosynthetic rate(Pn), transpiration rate(Tr) and stomatal conductance(Gs) of leaves increased initially then decreased with the increase of nitrogen concentration, and the intercellular CO2 concentration(Ci) decreased. The content of indigo in leaves gradually increased with the increase of nitrogen concentration, and the content of indirubin showed a trend of decreasing initially and then increasing. The content of total flavonoid in leaves showed a tendency of declining with the increase of nitrogen concentration. The content of (R,S)-epigoitrin in roots increased initially and then decreased with the increase of nitrogen concentration, and the content was highest under N3 treatment. The results indicated appropriate nitrogen supply is conducive to the accumulation of indigo and (R,S)-epigoitrin, while low nitrogen condition is favorable for increasing the contents of indirubin and total flavonoid. The (R,S)-epigoitrin yield in per plant was the highest under N3 treatment, indicating that suitably reduced nitrogen application could obtain Radix Isatidis with higher contents of active components. The study provides a theoretical reference for the reasonable application of nitrogen in the standardized cultivation of I. indigotica Fort. %U https://www.hnxb.org.cn/EN/10.11869/j.issn.100-8551.2019.10.2077