title: Light intensity affects the uptake and metabolism of glycine by pakchoi (Brassica chinensis L.).
abstract: The uptake of glycine by pakchoi (Brassica chinensis L.), when supplied as single N-source or in a mixture of glycine and inorganic N, was studied at different light intensities under sterile conditions. At the optimal intensity (414 μmol m(-2) s(-1)) for plant growth, glycine, nitrate, and ammonium contributed 29.4%, 39.5%, and 31.1% shoot N, respectively, and light intensity altered the preferential absorption of N sources. The lower (15)N-nitrate in root but higher in shoot and the higher (15)N-glycine in root but lower in shoot suggested that most (15)N-nitrate uptake by root transported to shoot rapidly, with the shoot being important for nitrate assimilation, and the N contribution of glycine was limited by post-uptake metabolism. The amount of glycine that was taken up by the plant was likely limited by root uptake at low light intensities and by the metabolism of ammonium produced by glycine at high light intensities. These results indicate that pakchoi has the ability to uptake a large quantity of glycine, but that uptake is strongly regulated by light intensity, with metabolism in the root inhibiting its N contribution.
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: Ministry of Education Key Lab of Environmental Remediation and Ecosystem Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, 310058, 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: Lianghuan
authors.initials: L
authors.lastname: Wu
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: Wenhai
authors.initials: W
authors.lastname: Mi
authors.affiliation: Ministry of Education Key Lab of Environmental Remediation and Ecosystem Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, 310058, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Feng
mesh_terms: D000596:Amino Acids / Q000378:metabolism; D064751:Ammonium Compounds / Q000378:metabolism; D018533:Biomass; D001937:Brassica / Q000378:metabolism* / Q000528:radiation effects*; D005998:Glycine / Q000378:metabolism*; D008027:Light; D009566:Nitrates / Q000378:metabolism; D009584:Nitrogen / Q000378:metabolism; D010788:Photosynthesis; D018517:Plant Roots / Q000378:metabolism
chemical_list: D000596:Amino Acids; D064751:Ammonium Compounds; D009566:Nitrates; D009584:Nitrogen; D005998:Glycine