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作者	单位
康华靖, 王巍伟, 权伟, 杨翔, 欧阳竹	(1.温州科技职业学院，浙江温州 325006 2.中国科学研究院地理科学与资源研究所生态网络观测与模拟重点实验室，北京100101 3.中国科学研究院禹城综合试验站，北京 100101 4.中国科学研究院研究生院，北京 100101)

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中文摘要:

为给C₃作物光呼吸等光合参数以及光响应模型和CO₂响应模型的研究提供参考，定量研究了小麦花期旗叶光呼吸速率对光强和CO₂浓度的响应。结果表明，在21%和2%O₂下小麦旗叶光饱和点分别为1 960.629和2 030.120 μmol·m^-2·s^-1。在较弱光强(小于800 μmol·m^-2·s^-1)下，小麦的总光呼吸速率(R_pt)与表观光呼吸(R_pa)均随着光强的升高而增大；当光强大于800 μmol·m^-2·s^-1时，R_pt和R_pa趋于稳定；整体上，不同光强下R_pt与R_pa之间差异较小(P>0.05)，这主要是由于在380 μmol·mol^-1 CO₂下，光呼吸的CO₂回收利用率较低。饱和光强下，R_pa随着CO₂浓度的增加呈先上升后下降的趋势，R_pa最大值(Rpmax)所对应的外界CO₂浓度为600 μmol·mol^-1，而R_pt则随着CO₂浓度的升高而降低；在低浓度CO₂(小于380 μmol·mol^-1)条件下，R_pt与R_pa之间差异显著(P<0.05)。R_pt与羧化速率的比值(R_pt /Vc)随着胞间CO₂浓度的升高而呈下降的趋势，而不同光强下R_pt /Vc相对稳定，整体上未达到显著水平(P>0.05)。

英文摘要:

Using gas exchange method, the response of photorespiration of wheat to different light intensities and CO₂ concentrations were estimated. The saturating light intensity of wheat flag leaf was 1 960.63 μmol·m^-2·s^-1 and 2 030.12 μmol·m^-2·s^-1 for 21% O₂ and 2%O₂, respectively. The apparent photorespiration (R_pa) and total photorespiration (R_pt) of wheat increased as PAR increased from 50 to 800 mol·m^-2·s^-1, and then reached a steady state. There were no significant differences between R_pa and R_pt at different light intensities (P>0.05), which accounted for the low recovery of photorespiration CO₂ at 380 μmol·mol^-1 CO₂. As CO₂ concentration increased, R_pa of wheat increased first, and then reached a maximum at 600 μmol·mol^-1, while R_pt decreased with CO₂ concentration increasing. There were significant differences between R_pa and R_pt when CO₂ concentration was lower than 380 μmol·mol^-1 CO₂ (P<0.05). The ratio of total photorespiration rate and carboxylation rate (R_pt / Vc) deceased with CO₂ concentration increasing, and had a small fluctuation at different light intensities (P>0.05), which indicated that suitable high light intensity and high CO₂ concentration were helpful to improve carboxylation rate (Vc).

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