高大气CO2浓度下小麦旗叶光合能量利用对氮素和光强的响应  

The responses of photosynthetic energy use in wheat flag leaves to nitrogen application rates and light density under elevated atmospheric CO_2 concentration

作　　者：张绪成[1,2,3] 于显枫[1] 马一凡[1] 上官周平[2] 

机构地区：[1]甘肃省农业科学院农业部西北作物抗旱栽培与耕作重点开放实验室,兰州730070 [2]中国科学院水土保持研究所,黄土高原土壤侵蚀与旱地农业国家重点实验室,杨陵712100 [3]中国农业大学资源环境学院,北京100094

出　　处：《生态学报》2011年第4期1046-1057,共12页Acta Ecologica Sinica

基　　金：国家自然科学基金(30800668)

摘　　要：采用开顶式气室盆栽培养小麦,设计2个大气CO2浓度、2个光照强度和2个氮水平的组合处理,通过测定小麦叶片光合速率-胞间CO2浓度响应曲线和叶绿素荧光参数,来测算小麦叶片光化学速率、光合电子传递速率以及叶绿体磷酸丙糖利用效率(TPU)等参数,研究施氮量和光强对高大气CO2浓度下小麦旗叶光合能量传递与分配的影响,以阐明全球气候变化下植物光合能量分配对光合作用适应性下调的作用机制及其氮素调控。结果表明,大气CO2浓度升高后小麦叶片的光呼吸电子传递速率(J0)和Rubisco氧化速率(V0)显著下降;光合电子流的光化学传递速率(JC)、Rubisco羧化速率(VC)和TPU则明显升高,而且施氮后变化幅度加大;小麦叶片JC/JF(PSⅡ反应中心总电子流速率)和TPU/VC显著增加,经过PSⅡ反应中心的电子流更多地进入碳同化过程,表现较高的光合速率(Pn)。遮荫提高了叶片光化学速率和PSⅡ反应中心总电子流速率(JF),这一作用在低氮叶片尤为突出,但使得J0和V0明显升高,并显著降低JC/JF,所以Pn明显下降。正常光照条件下,增施氮素可提高小麦叶片的JF、JC、VC和TPU,并使高大气CO2浓度下J0和V0较正常大气CO2浓度处理显著降低,有效地提高了植物叶片对光能的利用效率;遮荫后高大气CO2浓度下小麦叶片JC、VC、TPU、JC/JF和TPU/VC显著高于正常大气CO2浓度处理,而且这一变化不受氮素水平的显著调节。因此,氮素在高大气CO2浓度下对小麦叶片光合能量利用的调节因光强而异,正常光照下可显著改善小麦叶片对光合能量的利用状况,而遮荫后这一作用减弱。Nitrogen application rate is a critical factor led to photosynthesis acclimation of C3 plant under elevated atmospheric CO2 concentration.However,current knowledge is inadequate for the responses of photosynthetic electron transport and energy distribution of photosynthesis acclimation to nitrogen application rate in C3 plant under different light density.In this potted experiment,the Top Open Chambers was used to simulate the elevated atmospheric CO2 concentration,where wheat（Triticum aestivum L.） was grown with two N application rates（0g N/kg soil versus 2g N/kg soil）,two atmospheric CO2 concentrations（400μmol/mol versus 760μmol/mol） and two light flux density levels（natural light density versus 60% natural light density shadowed）.The photochemical rate of antenna excitation energy,photosynthetic electron transport rate and the triose phosphate utilization（TPU） estimated by fitting the biochemical model to A-Ci response curve and chlorophyll fluorescence parameters of wheat leaves at the heading stage.The electronic transport rate of photorespiration（J0） and Rubisco oxygenase rate（V0） decreased,the electronic transport rate of photochemistry（JC）,Rubisco carboxylase rate（VC） and TPU increased significantly by nitrogen nutrition supply,the JC/JF（total electronic transport rate of PSⅡreaction center） and TPU/VC increased significantly of wheat leaves under elevated atmospheric CO2 concentration,the more photosynthetic electron flux of PSⅡreaction center distributed into photochemical process,then net photosynthesis rate（Pn） increased.The photochemical rate and the total electronic transport rate of PSⅡreaction center（JF） increased,especially in wheat leaves with low-nitrogen concentration,However,the J0 and V0 increased,and JC/JF decreased under lower light flux density conditions,it indicated that the photorespiration function enhanced,though photochemical rate increased,but the more photosynthetic energy distributed into photorespiration,so the Pn decreased

关 键 词：大气CO2浓度 氮素 光强 电子传递速率 光能分配 小麦 

分 类 号：S512.1[农业科学—作物学]