不同土壤水分下绞股蓝细根形态及产量特征OA

To clarify the dynamic variation patterns in fine root morphological characteristics of Gynostemma longipes under different soil moisture conditions and their effects on yield and quality,one-year-old G.longipes was used as the experimental material,and four different irrigation treatments were set up,including CK(rain-fed),WW(soil water potential of-20 kPa),MS(soil water potential of-55 kPa),and SS(soil water potential of-75 kPa).During the growing season,biomass,relative saponin content,and fine root morphological characteristics(root length density,root surface area,root diameter,root tissue density,and specific root length were periodically sampled and measured.The results showed that the aboveground biomass of G.longipes was significantly lower under CK than the other three treatments in August(leaf harvesting season).In addition,the underground biomass of G.longipes under the SS was significantly increased by 60％compared with CK(P<0.05).However,no significant differences were observed in the relative contents of total saponins in the leaves and roots among different soil water treatments during the experiment.Therefore,an initial soil water potential threshold of-75 kPa was conducive to improving yield and maintaining quality of G.longipes cultivated in this region.This experiment also found that root tissue density was the main morphological indicator affecting the aboveground biomass and total biomass of G.longipes,while specific root length was the main fine root morphological indicator influencing underground biomass(R2=0.79).A quantitative relationship model was established for the first time between the fine root morphology and yield formation of G.longipes in our study.The findings enrich the knowledge of root system characteristics in G.longipes and similar shallow-rooted herbaceous plants,providing a theoretical basis for precise water management of shallow-rooted medicinal plants.