title: Hexavalent chromium stress enhances the uptake of nitrate but reduces the uptake of ammonium and glycine in pak choi (Brassica chinensis L.).
abstract: Chromium (Cr) pollution affects plant growth and biochemical processes, so, the relative uptake of glycine, nitrate, and ammonium by pak choi (Brassica chinensis) seedlings in treatments with 0mgL-1and 10mgL-1Cr (VI) were detected by substrate-specific15N-labelling in a sterile environment. The short-term uptake of15N-labelled sources and15N-enriched amino acids were detected by gas chromatography mass spectrometry to explore the mechanism by which Cr stress affects glycine uptake and metabolism, which showing that Cr stress hindered the uptake of ammonium and glycine but increased significantly the uptake of nitrate. Cr stress did not decrease the active or passive uptake of glycine, but it inhibited the conversion of glycine to serine in pak choi roots, indicating that the metabolism of glycine to serine in roots, rather than the root uptake, was the limiting step in glycine contribution to total N uptake in pak choi. Since Cr affects the relative uptake of different N sources, a feasible way to reduce Cr-induced stress is application of selective fertilization, in particular nitrate, in pak choi cultivation on Cr-polluted soil.
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: National Engineering Laboratory for Efficient Utilization of Soil and Fertilizer Resources, Shandong Agricultural University, Taian, Shandong 271018, China.
authors.forename: Jinzhao
authors.initials: J
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; 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; 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. Electronic address: finm@zju.edu.cn.
authors.forename: Lianghuan
authors.initials: L
authors.lastname: Wu
mesh_terms: D000596:Amino Acids / Q000378:metabolism; D064751:Ammonium Compounds / Q000378:metabolism*; D001937:Brassica / Q000378:metabolism*; D002857:Chromium / Q000378:metabolism / Q000494:pharmacology*; D005998:Glycine / Q000378:metabolism*; D009566:Nitrates / Q000378:metabolism*; D018517:Plant Roots / Q000378:metabolism; D012989:Soil Pollutants / Q000494:pharmacology
chemical_list: D000596:Amino Acids; D064751:Ammonium Compounds; D009566:Nitrates; D012989:Soil Pollutants; D002857:Chromium; C074702:chromium hexavalent ion; D005998:Glycine
keywords: Ammonium; Glycine; Hexavalent chromium stress; Nitrate; Pak choi; Uptake and metabolism