响叶杨光合蒸腾和水分利用效率对光强及CO_2浓度升高的响应

Response of photosynthesis rate,transpiration rate and water using efficiency of Populus adenopoda to light intensity and elevated CO_2 concentration

以2年生响叶杨幼树为试验材料,利用Li-6400便携式光合作用测定系统,对自然条件下响叶杨不同光合有效辐射(PAR)强度及不同CO2浓度(cCO2)处理下叶片光合及水分生理生态参数的变化特征进行了研究。结果表明:(1)400μmol/mol CO2摩尔分数条件下,响叶杨叶片净光合速率(Pn)与PAR之间的回归方程为:yPn=-1.0×10-5xP2AR+0.0303xPAR-1.1031,相关系数可达0.9882;光饱和点、光补偿点及表观量子效率分别为1515μmol/(m2.s)、55μmol/(m2.s)和0.045;叶片蒸腾速率(Tr)与PAR间回归方程:yTr=0.0026xPAR+7.1532,相关系数为0.878 6;叶片水分利用效率(WUE)与PAR间回归方程为:yWUE=-1.0×10-6x2PAR+0.0035xPAR-0.0933,相关系数为0.9493。(2)PAR为1000μmol/(m2.s)的条件下,Pn与CO2摩尔分数(cCO2)之间回归方程为:yPn=2.0×10-5x2CO2+0.0472xCO2-2.8523,相关系数为0.9502,CO2饱和点、补偿点及羧化速率分别为1180μmol/mol、64μmol/mol和0.058,但随cCO2增加Tr呈无规则变化,且两者无明显的相关关系;WUE与cCO之间的回归方程为:yWUE=3.0×10-6x2CO+0.0072xCO-0.4504,相关系数为0.9263。

Under the natural condition, the different intensities of photosynthetically active radiation （PAR） and different ranges of CO2 concentration, the characteristics of leaf photosynthesis and water eco-physiology of Populus adenopoda were studied to explore the response of photosynthesis, transpiration and water use efficiency to light intensity and elevated CO2 concentration by using two-years old young trees as materials. The results were as following： （ 1 ） Under the condition of 400μmol/mol CO2 , the regression equations between net photosynthesis rate （Pn） and PAR was yPn = - 1.0 × 10^-5x^2PAR ＋ 0. 0303xPAR - 1. 1031 with regression coefficient of 0. 9882; the light saturation point, light compensation point and apparent quantum yield （ AQY ） were 1515μmol/（ m^2·s） , 55 μmol/（ m^2·s） and 0. 045, respectively ; the regression equation between transpiration rate （Tr） and PAR was yTr = 0. 0026xPAR ＋ 7. 1532, which correlation coefficient is 0. 8786; and the regression equation between water using efficiency （WUE） and PAR was yWCE = - 1.0 × 10^-6x^2PAR ＋ 0. 0035xPAR-0. 0933, and its correlation coefficient was 0. 9493. （2） Under the condition of 1000 μmol/（ m^2 ·s） PAR, the regression equation between Pn and CO2 concentration was yPn = 2.0 × 10^-5x^2CO2 ＋ 0. 0472 x^2CO^2 - 2. 8523 with r equaled to 0. 9502, CO2 saturation point, CO2 compensation point and carboxylation efficiency were 1180μmol/mol, 64 μmol/mol and 0. 058, respectively; However, Tr changed randomly with the increment of CO2 concentration, and there was no significant correlation between them; the regression equation between WUE and CO2 concentration was yWUE=3.0×10^-6x^2CO2,＋0.0072xCO2-0.4504,（r=0.9263）.