Impact of nitrogen supply on carbon/nitrogen allocation: a case study on amino acids and catechins in green tea [Camellia sinensis (L.) O. Kuntze] plants*

Abstract

The concentrations of free amino acids (AA) and polyphenols (PP) are important determinants of green tea quality. Levels of AA and PP are governed interactively by nitrogen (N) supply and carbon (C) status, so the impact of C/N allocation on green tea quality was investigated in saplings cultivated hydroponically with 0.3, 0.75, 1.5 or 4.5 mmol l(-1) N. Activities of glutamine synthetase (GS), phenylalanine ammonia lyase (PAL), and phosphoenolpyruvate carboxylase (PEPC) were determined, as were concentrations of AA, PP and soluble sugars. Concentrations of AA increased with increasing N supply, and the AA profile was shifted towards AA characterised by low C/N ratios (arginine, glutamine) and away from theanine, the unique non-protein AA that is abundant in Camellia sinensis. High N supply significantly reduced the concentrations of PP in young shoots, and was accompanied by lower levels of carbohydrates (soluble sugars). Analysis of the C and N status and selected enzyme activities, combined with path coefficient analysis of variables associated with C and N metabolism, demonstrated increasing deviation of C flux to AA under abundant N supply. Accumulation of AA and PP depended strongly on N status, and the balance shifted toward increasing synthesis of AA associated with enhanced growth, while investment of C in secondary metabolites did not change proportionally under the condition of ample N supply.

Photosynthetic and Antioxidant Performance Are Differentially Affected by Short-Term Nitrogen Supply in Highbush Blueberry Cultivars at the Short-Term

“…The negative impacts of a high NH 4 + accumulation in plant tissues might be a consequence of Discussion Nitrogen (N) is an essential nutrient for photosynthesis, plant growth and development. It is also involved in the regulation of secondary metabolite synthesis, mainly in phenolic compounds (Ruan et al, 2010). In this study, the effects of different short-term N treatments on the chemical, physiological and biochemical characteristics of highbush blueberry were evaluated.…”

“…Nitrogen (N) is well recognized as an essential element for plant growth and also regulates the synthesis of secondary metabolites, such as phenolic compounds (Ruan et al, 2010). Dissimilar responses to N supply have been observed to enhance, diminish or not influence phenolic compound accumulation in plants (Fritz et al, 2006;Mogren et al, 2006).…”

Effects of organic fertilizers on the vegetative, nutritional, and productive parameters of blueberries ‘Corona’, ‘Legacy’, and ‘Liberty’

“…In contrast, the control without N had the lowest values, and the lack of N limited the synthesis of proteins, nucleic acids, phospholipids, and a number of secondary metabolites (Miller and Cramer, 2004), which affected vegetative development and the next reproductive stage. The application of N sources from different origins and composition promotes the growth of beneficial soil microorganisms associated with the root system of blueberries, higher uptake capacity, and essential nutrient concentration (Ruan et al, 2010). Treatment S (N as sodium nitrate) had a negative effect on the blueberries, which is explained by fast Na release in the sandy loam soil that produces toxicity in blueberries (Bryla and Machado, 2011;Bañados et al, 2012).…”

Effect of Varying Ratios and Rates of Enriched Cattle Manure on Leaf Nitrogen Content, Yield and Quality of Tea (Camellia sinensis)

“…Higher N rate had significantly lower the TF levels. Increase in N rate has been noted to increase the accumulation of free amino acid but reduce production of catechins (Ruan et al, 2010). Presence of free amino acids and catechin favour green and black tea quality respectively (Mukai et al, 1992).…”