title: Effects of glucose on the uptake and metabolism of glycine in pakchoi (Brassica chinensis L.) exposed to various nitrogen sources.
abstract: Plants can absorb amino acids as a nitrogen (N) source, and glucose is an important part of root rhizodeposition and the soil sugar pool, which participates in the regulation of plant growth and uptake. In pakchoi, the effect of glucose concentration on the glycine N uptake from a nutrient mixture composed of glycine, ammonium, and nitrate, or from a single N solution of glycine alone was studied using specific substrate15N-labeling and15N-gas chromatography mass spectrometry.
  
  
  
  The optimal glucose concentration for plant growth was 4.5 μM or 25 μM when supplied with glycine alone or the N mixture, respectively, and resulted in a >25% increase in seedling biomass. The addition of glucose affected the relative contribution from organic or inorganic sources to overall N uptake. When glucose was added at optimal concentrations, glycine was preferentially used as an N source, while the relative contribution from nitrate was reduced. The limiting step for glycine N contribution was active uptake in the roots in high glucose and single-N-source conditions; however, root metabolism of glycine to serine was limiting in high-glucose and mixed-N-source conditions.
  
  
  
  The addition of low concentrations of glucose increased the relative uptake of organic nitrogen and reduced the uptake of nitrate, suggesting a feasible way to decrease nitrate content and increase the edible quality of vegetables.
authors.affiliation: Ministry of Education Key Lab of Environmental Remediation and Ecosystem Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, 310058, China.|Zhejiang Provincial Key Laboratory of Subtropic Soil and Plant Nutrition, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, 310058, China.
authors.forename: Qingxu
authors.initials: Q
authors.lastname: Ma
authors.affiliation: State Key Laboratory of Rice Biology, China National Rice Research Institute, Hangzhou, 310006, China.
authors.forename: Xiaochuang
authors.initials: X
authors.lastname: Cao
authors.affiliation: Ministry of Education Key Lab of Environmental Remediation and Ecosystem Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, 310058, China.|Zhejiang Provincial Key Laboratory of Subtropic Soil and Plant Nutrition, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, 310058, China.
authors.forename: Yinan
authors.initials: Y
authors.lastname: Xie
authors.affiliation: Ministry of Education Key Lab of Environmental Remediation and Ecosystem Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, 310058, China.|Zhejiang Provincial Key Laboratory of Subtropic Soil and Plant Nutrition, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, 310058, China.
authors.forename: Han
authors.initials: H
authors.lastname: Xiao
authors.affiliation: Ministry of Education Key Lab of Environmental Remediation and Ecosystem Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, 310058, China.|Zhejiang Provincial Key Laboratory of Subtropic Soil and Plant Nutrition, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, 310058, China.
authors.forename: Xiaoli
authors.initials: X
authors.lastname: Tan
authors.affiliation: Ministry of Education Key Lab of Environmental Remediation and Ecosystem Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, 310058, China. finm@zju.edu.cn.|Zhejiang Provincial Key Laboratory of Subtropic Soil and Plant Nutrition, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, 310058, China. finm@zju.edu.cn.
authors.forename: Lianghuan
authors.initials: L
authors.lastname: Wu
mesh_terms: D000596:Amino Acids / Q000378:metabolism; D018533:Biomass; D001937:Brassica / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism*; D004798:Enzymes / Q000378:metabolism; D005947:Glucose / Q000378:metabolism* / Q000494:pharmacology; D005998:Glycine / Q000378:metabolism* / Q000493:pharmacokinetics; D018527:Hydroponics; D009584:Nitrogen / Q000378:metabolism*; D009587:Nitrogen Isotopes; D018517:Plant Roots / Q000378:metabolism; D018520:Plant Shoots / Q000378:metabolism
chemical_list: D000596:Amino Acids; D004798:Enzymes; D009587:Nitrogen Isotopes; D005947:Glucose; D009584:Nitrogen; D005998:Glycine
keywords: Brassica chinensis; Glucose; Glycine; Nitrogen uptake; Rhizodeposition; Soil nutrients