作 者 ：张志刚1,2，李 宏2*，DENNY WALTHER3，杨婵婵1,2，郭光华2
期 刊 ：西北植物学报 2012年 12期 页码：2506~2511
Keywords:Populus euphratica, P.pruinosa, gas exchange, environmental factors, water use efficiency,
摘 要 ：在自然条件下利用Li-6400光合作用系统对塔里木河中游地区的天然胡杨、灰叶胡杨净光合速率（Pn）、气孔导度(Gs)、胞间CO2浓度（Ci）、蒸腾速率（Tr）和水分利用效率（WUE）等生理指标进行测定分析，探讨它们对外界干旱环境适应的生理特性，为进一步研究胡杨、灰叶胡杨的光合水分生理特性，以及保护恢复塔里木河流域的天然胡杨林提供依据。结果表明：（1）在整个光合日变化进程中，胡杨的日平均Pn、Gs、Tr以及WUE均高于灰叶胡杨。（2）胡杨和灰叶胡杨的净光合速率日变化均呈“双峰”曲线并存在光合“休眠”现象。（3）胡杨、灰叶胡杨在正午时分出现的Pn下降主要是受到气孔限制的影响既气孔限制值增大、胞间CO2浓度减小；傍晚时分出现的光合速率下降主要是因受到外界光照强度减弱，既受非气孔限制影响较大。（4）决定胡杨和灰叶胡杨Pn日变化的环境因子作用大小均为：光量子通量密度（PPFD）>气孔导度（Gs）>空气相对湿度（RH）>气温（Tair）；决定胡杨与灰叶胡杨Tr日变化的环境因子作用大小顺序分别为：气温（Tair）>光量子通量密度（PPFD）>气孔导度（Gs）>空气相对湿度（RH）和光量子通量密度（PPFD）>气温（Tair）>气孔导度（Gs）>空气相对湿度（RH）。研究认为，胡杨与灰叶胡杨为适应干旱半干旱区的环境，在长期适应过程中形成了不同的生理生态对策，胡杨主要是通过调节Gs来有效控制蒸腾失水，提高WUE,进而适应干旱环境；灰叶胡杨主要是通过高蒸腾耗水，降低WUE来减少干旱环境对自身的伤害。
Abstract:With the Li-6400 system,we measured the diurnal change of photosynthetic rate(Pn),stomatal conductance (Gs),intercellular CO2 concentration(Ci),transpiration rate(Tr),water use efficiency(WUE) and other physiological indicators of Populus euphratica and P.pruinosa in the middle reaches of Tarim River.The purpose was to explore the physiological characteristics of adaptation to the arid environment and for further study the photosynthetic water physiological characteristics of P.euphratica and P.pruinosa as well as,to protect P.euphratica and P.pruinosa of Tarim basin and to provide research material and theoretical basis.The following results have been obtained:(1)In the entire process of the diurnal variation of photosynthesis,average of Pn,Gs,Ci,Tr and WUE of P.euphratica were higher than those of P.pruinosa.(2)The diurnal variation of photosynthetic rate of P.euphratica and P.pruinosa were double peak curve,and there are the phenomenon that “photosynthetic sleep”.(3)At noon,the photosynthetic rate of P.euphratica,P.pruinosa were decreased that the impact by stomatal limitation.In the evening,the photosynthetic rate of P.euphratica,P.pruinosa were decreased that the impact by the weakened light intensity,the greater impact by non-stomatal limitation.(4)Determine the photosynthetic rate changes of P.euphratica,P.pruinosa,the environmental factors as follows:pho-tosynthetic photon flux density (PPFD)>stomatal conductance (Gs)>air humidity (RH)>air temperature(Tair);decide the transpiration rate of P.euphratica,the environmental factors as follows:Tair>PPFD>Gs>RH;decide the diurnal variation transpiration rate of P.pruinosa the environmental factors as follows:PPFD>Tair>Gs>RH.The P.euphratica and P.pruinosa to adapt to the environment of the arid and semi-arid regions in the long process of adaptation to form different physiological and ecological strategy.P.euphratica improved WUE and took the initiative to adjust stomatic conductance to decrease transpiration,while P.pruinosa reduced the hurt of arid environment and drought with high transpiration and low WUE.