Analysis of the effect of topographical conditions on the artemisinin content in sweet wormwood herb in Guangxi, China
广西地形对青蒿中青蒿素含量的影响

With the increasing demands of artemisinin, artificial planting of Sweet Wormwood Herb is necessary. These are close relationships between topographical conditions and artemisinin content in Sweet Wormwood Herb. In order to explore the spatial variability of artemisinin content in Sweet Wormwood Herb and select most suitable planting regions, 155 samples of Sweet Wormwood Herb are collected from 31 sites in Guangxi, one of the main habitats of Sweet Wormwood Herb in China. The artemisinin content is analyzed precisely in the laboratory. Based on these sample data and GIS technology, the spatial relationships between topographical conditions and the artemisinin content in Sweet Wormwood Herb in Guangxi, China are examined statistically and spatially. First, there is a significant difference in artemisinin content in different sample sites statistically (P=0.000<0.05). Second, elevation and slope are the key terrain factors affecting the artmisinin content. The artmisinin content sampled from the mountainous regions is evidently higher than that from plain areas (P=0.000<0.05). Third, in southwest low-mountain Guangxi, the artmisinin content in herb sample is the highest, and in the southeast plain areas it is the lowest. It is also observed that artmisinin content reduces along with the increase of elevation, but increases along with the increase of slope. Forth, according to the artmisinin content in samples, regional suitability for artificial planning of Artemisia annua L. can be classified as most suitable, where the artmisinin content is between 0.76% and 0.93%, more suitable (0.61%-0.76%), suitable (0.47%-0.61%) and unsuitable (0.32%-0.47%). The northeast and southwest Guangxi, including the mountainous counties of Yangshuo, Yangshuo, Duan, Dahua, Pingguo, Mashan, Mingwu, Duan, Nanning and Chongzuo, are the most suitable. The most part of prefecture regions, such as Beihai, Qinzhou, Guigang, Hezhou, Wuzhou and Cenxi, are classified as unsuitable. Fifth, the topographical effect is complex in the north part of Guangxi, where the microclimate and micro-terrain is clearly presented. The authors believe that the ecological suitability research at small scale will be effective in.