Root exudates of alkaloids and flavonoids from Lupinus angustifolius plants

Root system traits play a crucial role in addressing current agricultural and environmental challenges. Because root dynamics and exudation are complex, researchers have used various approaches to investigate these processes. This study aims to assess Lupins (Lupinus angustifolius L.) plant biomass and test the effects of different collection media and collection duration on root exudation composition, focusing on alkaloids (13-hydroxylupanine, gramine, lupinine, lupanine, and sparteine) and flavonoids (apigenin, genistein, luteone, and rutin). The experiment included exudate collection intervals of 3–72 h and covered dynamic changes from 10 to 110 d after sowing (DAS). Deionized water and CaCl2 treatments were used as collection media to collect both alkaloids and flavonoids. The results revealed that fresh root weight reached its maximum at 90 DAS, while root dry weight and root length peaked at the final interval of 110 DAS. Root exudate collection from 20-day-old lupin roots using deionized water and CaCl2 as collection solutions indicated that deionized water facilitated the highest exudation of both alkaloids and flavonoids. Furthermore, exudate collection over 24 h with deionized water yielded the highest exudation of both alkaloids and flavonoids. Alkaloid exudation was significantly influenced throughout the growing season from 20 to 110 DAS. Similarly, flavonoid exudation fluctuated over time, with the highest levels recorded during the final growth stages. These findings provide insights into the dynamics of root exudation and may improve understanding of plant–soil interactions, secondary metabolite release, and adaptation in lupin and other species.