Abstract: Potassium nutrition plays an important role in plant growth and development. The effects of improved potassium levels on alkaloid metabolism and biomass accumulation in Catharanthus roseus under different levels of exogenous potassium were explored in the present study. The results showed that exogenous potassium nutrition significantly increased the plant height, root length, total biomass of C.roseus. The most significant effect was observed at the concentrations of 10 and 15 mmol·L^-1. In addition, improved exogenous potassium nutrition significantly increased indole alkaloid contents. The content of catharanthine was increased with the increase of the potassium nutrition concentration. Vindoline and vinblastine contents were increased first and then reduced, reaching the maximum at 15 mmol·L^-1 and high potassium nutrition concentration was not conducive for the synthesis of them.

Key words: Catharanthus roseus, potassium nutrition, alkaloid, accumulation