低氮条件下高CO2浓度促进油菜NO3-吸收的生长素调控机理

作物对氮素的需求随大气CO2浓度的升高而增加，这在我国化肥减施的背景下，易导致碳氮供给矛盾，引发作物碳氮代谢失衡。本项目以前期研究发现的低氮高CO2浓度下，油菜NO3-吸收和色氨酸、生长素含量均显著升高的现象为切入点，通过在低氮条件下设置不同CO2浓度处理，测定油菜光合速率、CO2同化、NO3-吸收、氮素累积等指标，明确低氮条件下高CO2浓度对油菜CO2同化和NO3-吸收的影响；测定DAHP、色氨酸、生长素等的合成指标，探明低氮条件下油菜生长素合成对高CO2浓度的响应。设置不同CO2浓度和外源IAA处理，测定NO3-吸收、NO3-吸收转运蛋白及转运能量，根系构型等，探明低氮条件下油菜NO3-吸收对高CO2浓度和外源IAA的响应，从而揭示低氮条件下高CO2浓度促进油菜NO3-吸收的生长素调控机理。对促进油菜碳氮营养高效协同利用和油菜产业绿色可持续发展具有重要意义。

The demand of Nitrogen (N) of crops were increased with the increasing of atmospheric CO2 concentration, it is easy to lead to the contradiction of carbon and nitrogen supply and imbalance of carbon and nitrogen metabolism under the background of reducing fertilizer application. Based on the appearance of the absorption of NO3- and the contents of tryptophan and auxin in Brassica napus were significantly increased under the condition of low N and high CO2 concentration, treatments make up by different CO2 concentrations were set up in this study. The photosynthetic rate, CO2 assimilation, NO3- uptake and N accumulation were all asssayed to study the effects of high CO2 concentration on the CO2 assimilation and NO3- uptake of Brassica napus under the low N condition. The synthesis of DAHP, tryptophan and auxin were all determined to study the response of auxin synthesis of Brassica napus to the high CO2 concentration under low N condition. Besides, different CO2 concentrations and exogenous IAA treatments were set up in this study, and the NO3- absorption, NO3- transporter and the energy for NO3- absorbing, root architecture were all asssayed to study the response of NO3- uptake to the high CO2 concentration and to the exogenous IAA under low N condition. Thus, the mechanisms of auxin regulation on the high CO2 concentration promotes NO3- uptake of Brassica napus under low N condition was revealed. This study is of great significance to promote the efficient co-utilization of carbon and nitrogen nutrition and to the green and sustainable development of rapeseed industry.