大气NH_3升高对不同供氮水平下小麦叶片光合生理特征的影响

Effects of Elevated NH_3 on the Photosynthetic Physiological Characteristics in Winter Wheat Leaf with Various N levels

以小麦品种‘小偃6号’(氮高效品种)和‘长旱58’(氮低效品种)为材料,采用开顶式气室和土培实验研究了大气NH3浓度升高对生长于高、低两种供氮介质下小麦植株不同生育期叶片净光合速率(Pn)、气孔导度(Gs)、叶绿素含量、叶绿素荧光参数(Fv/Fm、Fv/F0)和可溶性糖含量的影响。结果显示:两小麦品种高氨低氮处理植株的Pn、Fv/F0和可溶性糖含量均高于高氨高氮和低氨低氮处理,并在生育后期差异达显著水平(P<0.05),氮低效品种的Gs也符合上述规律且不同处理间差异显著(P<0.05);小麦各生育期高氨高氮处理下植株的Pn均显著低于低氨高氮处理,且两处理间灌浆期的叶绿素含量和灌浆期以前的可溶性糖含量的差异显著(P<0.05),而两处理灌浆期以前的叶绿素荧光参数Fv/Fm在各处理条件下均无显著差异;不同处理间及品种间各项光合特征指标差异缺乏规律性。可见,大气中NH3浓度升高有利于改善低供氮介质条件下小麦植株的氮营养状况,但不同氮效率品种间的响应存在差异。

The experiment was carried out in Open Top Chamber（OTCS）, The main aim of this study was to investigate the response of various photosynthesis parameters,e, g. , net photosy conductance（G,）, chlorophyll content, chlorophyll fluorescence characteristics （Fv/Fm, Fv/Fo ） and soluble sugar content in two wheat cultivar types to elevated NH3 concentration. The results showed that：The value of Fv/Fm had no significant change in treatments. In the High NH3 ＋Low N treatment,the values of Pn,Fv/Fo and soluble sugar were higher than those both of High NHa＋High N and Low NH3＋Low N treatments（especially in the late growth stage）. The value of G5 was also according above regularity only in nitrogen inefficiency crop,and the difference of different treatments was significant（P〈0.05）. In the High NH3 tHigh N treatment,the value of Pn was all significantly（P〈0.05） lower than those in the Low NH3 ＋ High N treatment at every growth stage. However, it appeared at filling stage for chlorophyll content and before filling stage for soluble sugar content. But the difference of photosynthesis parameters between crop types was no obvious. All these results suggest that increased atmospheric NH3 can enhance the status of nitrogen nutrition of winter wheat growing in low N medium, but the result of being more significantly positive effect on low nitrogen efficiency cultivar still need further study.