FACE条件下冬小麦的光合适应

Photosynthetic Acclimation of Winter Wheat under Free Air CO_2 Enrichment(FACE)

利用开放式CO2浓度升高(Free Air Carbon dioxide Enrichment)系统平台,于冬小麦开花期、乳熟期对旗叶进行气体交换测量,根据光合模型计算光合参数,研究550μL.L-1CO2对冬小麦旗叶光合能力的影响。结果表明,无论是在冬小麦开花期还是乳熟期,FACE圈内的小麦叶片在短时间高CO2浓度下初始出现的光合速率增强逐渐减弱或消失,即FACE圈内的小麦叶片表现出对高CO2浓度的光合适应现象。低氮、常规施氮水平下均发现了小麦旗叶的光合适应现象,但是光合适应现象与施氮量没有显著的线性关系。另外,研究发现,FACE系统中,冬小麦旗叶的SPAD值和叶绿素含量降低,这可能是导致FACE系统中小麦叶片出现光合适应现象的原因。

Gas exchange was measured for flag leaf of winter wheat in the flowering and dough stage under the free air CO2 enrichment （FACE） system. Photosynthetic parameters were also calculated by using a biochemical model. Research was conducted on the effect of the response curves and photosynthetic parameters with elevated CO2 （550 μL·L^-1）. The results showed that the net photosynthesis rate, which increased with CO2 concentration in short term, decreased even disappeared in FACE rings both at flowering stage and dough stage. That means photosynthetic acclimation occurred in the flag leaf of winter wheat in FACE rings. There was not liner relationship between photosynthetic acclimation and N supply. SPAD and chlorophyll content in the flag leaf decreased with elevated CO2, which probably was main reason for photosynthetic acclimation.