[Spatio-temporal root distribution and yield characteristics of Epimedium pubescens in Chinese medicinal...

Clarifying the two-dimensional spatial distribution and the seasonal yield dynamics of Epimedium pubescens roots in agroforestry systems can provide an ecological theoretical basis and technical support for optimizing the understory cultivation patterns of E. pubescens. E. pubescens plants cultivated in Ginkgo biloba forests(YX), Phellodendron amurense forests(HB), and monocropping fields(CK) were taken as research subjects. Stratified sampling was conducted during the summer and winter harvest seasons to analyze root spatial distribution, morphological characteristics, and biomass allocation. Additionally, high-performance liquid chromatography(HPLC) was employed to determine the total flavonol glycoside content. The results demonstrated that the spatial distribution of E. pubescens roots exhibited significant differences among planting patterns. Specifically, the HB group showed a significantly higher proportion of fine roots in the surface soil layer(0-10 cm) than the YX and CK groups, whereas the YX group displayed more extensive root distribution in deeper soil layers(30-50 cm) than the HB and CK groups. The root morphology of E. pubescens was significantly influenced by planting patterns and seasonal variations. In summer, the root length density of E. pubescens in the YX group decreased by 56%-75%(P<0.05) in the 0-20 cm soil layer compared with that in the CK group, whereas in winter, both agroforestry systems showed significantly higher root length density than the CK group. No significant difference was observed in aboveground or belowground biomass of E. pubescens among different planting patterns. However, the YX group exhibited significantly higher root biomass allocation ratio and significantly lower rhizome biomass allocation ratio than the CK and HB groups. These findings indicate that E. pubescens roots exhibit remarkable phenotypic plasticity, enabling adaptive adjustment strategies to enhance resource acquisition efficiency in agroforestry systems.