CO_2浓度对冬小麦氮代谢的影响

Effect of CO_2 Concentration on Nitrogen Metabolism of Winter Wheat

采用全硝态氮霍格兰营养液为培养基质,在自然光与遮光条件下分别对冬小麦植株进行增加CO2浓度处理,分期测定其体内NO3-N、NH4-N、全氮量、吸氮量及硝酸还原酶活性(NRA),研究CO2对小麦氮代谢的-+影响。结果表明,无论遮光与否,增加CO2浓度均增强了植株对NO3-N的吸收、同化能力。但对地上部与根部-的影响不同,施加CO2,地上部硝态氮、铵态氮浓度及NRA均有所降低,而植株由溶液中吸收的硝态氮及吸氮总量增加;与地上部相比,CO2对根部硝态氮、铵态氮浓度影响较小,趋势相似;培养期间,施CO2极显著的提高根部NRA,增强根部对硝态氮的同化能力。

Hoagland’s solution of water culture medium was used to study the effect of CO2elevated on nitrate metabolism of wheat under normally natural light and light-shaded conditions. NO3 -N, NH4 -N, nitrate reductase activity, total uptake N by wheat - + plants during solution cultural period and total N in plants were determined for comprehensive evaluation of the effect. Results showed that under both natural light and light-shaded conditions, addition of CO2 increased NO3 -N uptake and its assimilative - capabilities by plants. However, there were some difference between shoots and roots. With increase of CO2 concentration, the concentration of NO3 -N and NH4 -N as well as nitrate reductase activity all decreased in shoots while the difference was not so - + distinct in roots, and the nitrate reductase activity did not decrease, but increase. Since NO3 -N uptake by plants from the solution and - the total N in plants were much enhanced by CO2 addition, it may be concluded that addition of CO2 has resulted in rise of nitrate absorption, assimilation and metabolism of wheat.