Ma Qingxu, Cao Xiaochuang, Ma Jinzhao, Tan Xiaoli, Xie Yinan, Xiao Han, Wu Lianghuan
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.
State Key Laboratory of Rice Biology, China National Rice Research Institute, Hangzhou 310006, China.
Ecotoxicol Environ Saf. 2017 May;139:384-393. doi: 10.1016/j.ecoenv.2017.02.009. Epub 2017 Feb 23.
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 and 10mgL Cr (VI) were detected by substrate-specific N-labelling in a sterile environment. The short-term uptake of N-labelled sources and N-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.
铬（Cr）污染会影响植物生长和生化过程，因此，在无菌环境中通过底物特异性N标记检测了小白菜（Brassica chinensis）幼苗在0mg/L和10mg/L Cr（VI）处理下对甘氨酸、硝酸盐和铵的相对吸收。通过气相色谱质谱法检测N标记源和富含N的氨基酸的短期吸收，以探究Cr胁迫影响甘氨酸吸收和代谢的机制，结果表明Cr胁迫阻碍了铵和甘氨酸的吸收，但显著增加了硝酸盐的吸收。Cr胁迫并未降低甘氨酸的主动或被动吸收，但抑制了小白菜根系中甘氨酸向丝氨酸的转化，这表明根系中甘氨酸向丝氨酸的代谢，而非根系吸收，是甘氨酸对小白菜总氮吸收贡献的限制步骤。由于Cr会影响不同氮源的相对吸收，在受Cr污染土壤上种植小白菜时，一种可行的减轻Cr诱导胁迫的方法是进行选择性施肥，尤其是施用硝酸盐。
