title: Centelloside accumulation in leaves of Centella asiatica is determined by resource partitioning between primary and secondary metabolism while influenced by supply levels of either nitrogen, phosphorus or potassium.
abstract: In the present study we aimed to investigate the relevance of either N, P or K supply for herb and leaf yield and for centelloside concentrations in Centella asiatica L. Urban leaves. In this regard, we elucidated the causal relationship between assimilation rate, leaf N, P and K concentrations, herb and leaf production, and centelloside accumulation. The experiments were conducted consecutively in a greenhouse where C. asiatica was grown in hydroponic culture and fertigated with nutrient solutions at either 0, 30, 60, 100 or 150% of the N, P or K amount in a standard Hoagland solution. In general, the increase in N, P or K supply enhanced assimilation rate and herb and leaf yield. However, exceeding specific thresholds, the high availability of one single nutrient caused lower leaf N concentrations and a decline in assimilation rate and plant growth. Irrespective of N, P and K supply, the leaf centelloside concentrations were negatively associated with herb and leaf yield, which is in accordance with the assumptions of the carbon/nutrient balance and the growth differentiation balance hypotheses. Moreover, we found strong negative correlations between saponins and leaf N concentrations, while the respective sapogenins were negatively correlated with K concentrations. Using C. asiatica as model system, our experiments reveal for the first time that the accumulation of saponins and sapogenins is affected by resource allocation between primary and secondary metabolism and that besides carbon, also nutrient availability is relevant for the regulation of the centelloside synthesis. Finally, our results highlight the huge potential of optimized and carefully controlled mineral nutrition of medicinal plants for steering the bio-production of high-quality natural products.
authors.affiliation: Institute of Crop Science and Resource Conservation-Horticultural Sciences, University of Bonn, Auf dem Hügel 6, 53121 Bonn, Germany.
authors.forename: Viola
authors.initials: V
authors.lastname: Müller
authors.forename: Christa
authors.initials: C
authors.lastname: Lankes
authors.forename: Benno F
authors.initials: BF
authors.lastname: Zimmermann
authors.forename: Georg
authors.initials: G
authors.lastname: Noga
authors.forename: Mauricio
authors.initials: M
authors.lastname: Hunsche
mesh_terms: D028041:Centella / Q000254:growth & development / Q000378:metabolism*; D006027:Glycosides / Q000378:metabolism*; D018527:Hydroponics; D008903:Minerals / Q000378:metabolism*; D009584:Nitrogen / Q000378:metabolism; D010758:Phosphorus / Q000378:metabolism; D010788:Photosynthesis; D018515:Plant Leaves / Q000254:growth & development / Q000378:metabolism; D011188:Potassium / Q000378:metabolism; D012502:Sapogenins / Q000378:metabolism*; D012503:Saponins / Q000378:metabolism*; D064210:Secondary Metabolism; D012987:Soil / Q000737:chemistry; D014315:Triterpenes / Q000378:metabolism*
chemical_list: D006027:Glycosides; D008903:Minerals; D012502:Sapogenins; D012503:Saponins; D012987:Soil; D014315:Triterpenes; D010758:Phosphorus; D009584:Nitrogen; D011188:Potassium
keywords: Asiaticoside; CNB; DM; ESI-MS; GDB; Glu; HPLC; HY; K; LY; N; Nutrient; OPPP; P; PAR; Photosynthesis; Pn; Rha; Saponin; Trade-off; WTA; assimilation rate; carbon/nutrient balance hypothesis; dry mass; electrospray ionization-mass spectrometry; glucose; growth differentiation balance hypothesis; herb yield; high-performance liquid chromatography; leaf yield; nitrogen; oxidative pentose phosphate pathway; phosphorus; photosynthetic active radiation; potassium; rhamnose; weeks of treatment application