[Effects of understory environmental factors on dynamic variations in yield and active constituent content of...

Elucidating the effects of understory environmental factors on the yield and active constituent content of medicinal plants is essential for standardizing understory cultivation techniques in medicinal plant production. This study focused on Epimedium pubescens cultivated under forest canopies. By dynamically monitoring understory environmental factors across three plantations(Phellodendron amurense, Camptotheca acuminata, and Phoebe zhennan) and open-field cultivation(CK), this study assessed variations on different spatial scales(varying forest stands and understory positions) and temporal scales. Dynamic sampling and analysis of E. pubescens yields and flavonol glycoside content were conducted, elucidating the dynamic variation characteristics and influencing factors of both the yield and active constituent content of E. pubescens in understory cultivation. The results demonstrated that:(1)The spatial variations in understory environmental factors depended on tree species characteristics and stand density, while maintaining consistent patterns across temporal scales.(2)The yields of E. pubescens and the total flavonol glycoside content in the inter-row space of the three plantations were comparable to those of CK, while the yield of E. pubescens in the inter-row space increased by 90%(P. amurense), 101%(C. acuminata), and 107%(P. zhennan), respectively, compared with that under the canopy.(3)Understory air humidity was the environmental factor contributing most significantly to the yield formation of E. pubescens. The harvest yield could be quantitatively expressed by an exponential function of air humidity(y=0.167 7e~(0.072 4x), P<0.05, R~2=0.45). These findings provide theoretical guidance and technical support for the understory cultivation of E. pubescens and similar medicinal plants.