Carbon and nitrogen metabolism under nitrogen variation affects flavonoid accumulation in the leaves of <i>Coreopsis tinctoria</i>

Flavonoids are phytochemicals present in medicinal plants and contribute to human health. Coreopsis tinctoria , a species rich flavonoids, has long been used traditional medicine as food resource. N (nitrogen) fertilization can reduce flavonoid accumulation C. . However, there is limited knowledge regarding regulatory mechanisms. The aim of this study was determine the effect availability on biosynthesis investigate relationship between C (carbon) metabolism coupled with synthesis under controlled conditions. seedlings were grown hydroponically five different levels (0, 0.625, 1.250, 2.500 5.000 mM). related indexes C, variation measured analysed. (low moderate levels) regulates enzyme activities metabolism, promotes carbohydrates, reduces metabolite levels, enhances internal C/N balance. content roots stalks remained relatively stable, while that leaves peaked at low or intermediate levels. closely phenylalanine ammonia-lyase (PAL), cinnamate 4-hydroxylase (C4H), 4-coumarate: coenzyme A ligase (4CL), chalcone-thioase (CHS) activity, significantly positively correlated carbohydrates negatively metabolites. Thus, not only control distribution amino acid carbohydrate pathways but also change pathways, which provides meaningful information for maintaining high yields ensuring nutritional value crop plants.