土壌の排水性がウラルカンゾウ（Glycyrrhiza uralensis）の根のグリチルリチン酸含量と生育へ及ぼす影響

抄録

The purpose of this study was to evaluate the influence of environmental factors on the quality and growth of Glycyrrhiza uralensis and to validate the conditions suitable for their domestic cultivation in Japan. We found that the glycyrrhizic acid (GL) content of G. uralensis roots harvested from 10 field locations increased with the duration of cultivation. A significantly positive correlation was found between the GL content and the gaseous phase ratio at the 20-cm depth of soil during each year of cultivation for 3 years. We used multiple regression analysis with GL content as the objective variable and the cultivation period and the gaseous phase ratio at the 20-cm soil depth as explanatory variables. Thus, our model is able to explain 86% of variation in the GL content of the roots. The root productivity realized over a three-year period across 10 field locations could be classified into two types using the gaseous phase ratio at 60-cm soil depth and a threshold value of 0.10. In the experiment using a 1/2,000a Wagner pot with high (0.447) and low (0.058) gaseous phase ratio, the GL content of the G. uralensis root was significantly higher in plots with a high gaseous phase ratio. Based on the results of this multi-year, multi-location study, we propose that soils with a gaseous phase ratio of not less than 0.10 be selected to achieve favorable production of G. uralensis.