| 摘要: |
| 以小白菜为材料，设置4个镉（Cd）浓度水平以及3个氮素形态配比，分析镉-氮相互作用对小白菜生长及碳氮代谢相关指标的影响，结果表明：Cd的物质的量浓度为5 μmol·L-1时，对小白菜地上部分鲜重、总氮含量影响不显著；当Cd的物质的量浓度为50、100 μmol·L-1时，小白菜鲜重和总氮含量显著降低.无论是否添加Cd，硝铵比3/7处理的小白菜鲜重显著低于硝铵比10/0（全硝）和硝铵比7/3处理；100 μmol L-1Cd处理时小白菜地上硝酸盐的含量显著低于对照组，其余处理与对照差异不显著；不同Cd浓度处理均降低了小白菜的游离氨基酸含量，提高了其可溶性蛋白质含量.相对于全硝处理，以硝铵比7/3为氮源可提高50 μmol·L-1Cd处理时小白菜的总氮含量、游离氨基酸含量及100 μmol·L-1Cd处理的小白菜地上部分硝态氮含量.当以全硝及硝铵比7/3为氮源时，小白菜地上部分总碳含量随Cd浓度的增加而增加，而可溶性糖含量仅在100 μmol·L-1Cd处理时显著高于无镉对照组.小白菜地上部分总Cd含量随Cd处理浓度的增加而增加，但在全硝和硝铵比7/3处理间差异不显著.综上，不同硝铵比影响镉胁迫下小白菜的生长和碳氮积累，适宜硝铵配比有助于提高小白菜对镉的耐受性. |
| 关键词: 镉 硝态氮 铵态氮 小白菜 |
| DOI：10.3969/J.ISSN.1000-5137.2017.05.004 |
| 分类号:S634.3;S945.12 |
| 基金项目:国家自然科学基金青年基金（31601744）；上海市自然科学基金（15ZR1431300）；上海植物种质资源工程技术研究中心项目（17DZ2252700） |
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| Effects of nitrogen forms on pakchoi (Brassica chinensis) growth and its carbon and nitrogen accumulation under cadmium pollution |
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Xu Jia'nan, Wang Quanhua, Wang Xiaoli
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Development Center of Plant Germplasm Resources, College of Life and Environmental Sciences, Shanghai Normal University, Shanghai 200234, China
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| Abstract: |
| The effect of the NH4+/NO3- ratio on the growth of pakchoi (Brassica chinensis L.) and its carbon and nitrogen accumulation were analyzed under four cadmium levels treatments. Results showed that 5 μmol·L-1 Cd treatment had no significant effects on the fresh weights and the total nitrogen contents of pakchoi,while 50 μmol·L-1 Cd and 100 μmol·L-1 Cd treatments significantly reduced its fresh weights and total nitrogen contents. Irrespective of the Cd concentration,the fresh weight of pakchoi supplied N with the 3/7 ratio of NO3-/NH4+ was the lowest compared to other N treatments. Nitrate contents were significantly decreased under 100 μmol·L-1 Cd treatments. All Cd treatments reduced the free amino acid content but increased the soluble protein contents. When supplied with 30% NH4+,the contents of total N and free amino acids under 50 μmol·L-1 Cd as well as the nitrate content under 100 μmol·L-1 Cd treatments were increased. The total carbon contents of pakchoi increased with the cadmium concentration increasing. Only the soluble sugar contents under 100 μmol·L-1 Cd treatments were higher than those under control treatment. The total cadmium contents of pakchoi increased with the cadmium concentration increasing. No significant difference of total cadmium contents were found between the two NO3-/NH4+ ratio treatments (10/0 and 7/3). In conclusion,the NO3-/NH4+ ratio affects the growth of pakchoi and its carbon and nitrogen accumulation under cadmium pollution;the suitable NO3-/NH4+ ratio will help to improve the cadmium tolerance of pakchoi. |
| Key words: cadmium nitrate nitrogen ammonium nitrogen Brassica chinensis |
