Nitrogen and three chemical mimics of saponin precursors enhance biomass and calculation saponin for Gynostemma pentaphyllum under hydroponic conditions

Abstract

ABSTRACT: Gynostemma pentaphyllum (Thunb.) Makino (G. pentaphyllum) is used in traditional Chinese medicine to stimulate immune responses and reduce blood lipid concentrations, and has broad market growth prospects. In this study, a nutrient liquid culture method has been modified by adding nitrogen and or chemical mimic of saponin precursor to stimulate rooting from stem cuttings. Furthermore, total nitrogen concentration and ammonia/nitrate ratio in the nutrient solution has been optimized; And, the concentration of three ginsenosides precursors that applicated in nutrition solution together with total nitrogen and ammonium/nitrate ratio were studied. The results showed that, after 10 days of culture, adventitious roots developed from stem cuttings to form complete regenerated plantlets. The addition of 1 mg·L-1 indole acetic acid in hydroponic solution could effectively increase the length and number of adventitious roots. The optimal total nitrogen concentration in the nutrient solution for increase in fresh biomass of G. pentaphyllum was 7.0 mmol·L-1 and the optimal ammonium/nitrate ratio was 2:3 for increase in the plant fresh weight, and chlorophyll a, chlorophyll b, and total chlorophyll contents of G. pentaphyllum rooted cuttings. Addition to the nutrient solution of three chemical mimics of saponin precursors sodium acetate (0.5 mmol·L-1), geraniol (0.5 mmol·L-1), and DL-mevalonolactone (0.3 mmol·L-1) increased the content and yield of total saponins.

Keywords

• hydroponics
• Gynostemma pentaphyllum
• stem cutting
• nitrogen
• chemical mimics of saponin precursors