鸡爪槭光合特性对模拟酸雨的响应

研究了模拟酸雨（对照、pH 5.0、pH 4.0、pH 3.0、pH 2.0）胁迫对鸡爪槭（Acer palmatum Thunb.）叶片光合特性的影响。结果表明,试验前20 d,所有处理净光合速率日积分值（DIV of Pn）、蒸腾速率日积分值（DIV of Tr）及水分利用效率（WUE）日均值均显著高于对照（P〈0.05）。试验中后期（喷后40 d、喷后60 d）,pH 5.0的处理Pn日积分值均最高,WUE相对较高而Tr日积分值相对较低。pH≤4.0的处理在同一时期Pn日积分值、Tr日积分值均随pH值的降低而降低,WUE日均值变化趋势则相反。各处理Pn日积分值、Tr日积分值和WUE日均值均随试验时间的延长而降低。喷后60 d,pH 4.0的处理较pH 2.0和pH 3.0的处理WUE低而Pn日积分值和Tr日积分值则相反。综合分析表明,pH 5.0的酸雨处理有利于鸡爪槭叶片光合能力的发挥,酸度低于pH 3.0则会使光合能力下降,影响植株生长。

Response of simulated acid rain on photosynthetic characteristics of acer palmatum

The effects of simulated acid rain with different pH（CK、pH 5.0、pH 4.0、pH 3.0、pH 2.0） on photosynthetic characteristics in leaves of Acer palmatum were studied respectively.The results showed that diurnal integral value of photosynthesis（DIV of Pn）,diurnal integral value of transpiration rate（DIV of Tr）and daily average value of water use efficiency（WUE）of the seedlings in the all treatments were significantly higher than CK during the first 20 days of the experiment（P〈0.05）.During the middle and late period（40 days and 60 days after spraying acid rain） the DIV of Pn was the highest and the WUE was relatively high while the DIV of Tr was relatively low for the treatment of simulated acid rain at pH5.0.At the same times both DIV of Pn and DIV of Tr of the seedlings which were treated at pH4.0 and below gradually decreased with the acidity-increasing of acid rain.But the change trend of daily average value of WUE was opposite.The decreases of DIV of Pn,DIV of Tr and the daily average value of WUE was followed by treatments time.Furthermore,WUE of pH 4.0 was lower than that of pH 3.0 or pH 2.0 while both DIV of Pn and DIV of Tr of pH 4.0 were higher than that of pH 3.0 and pH 2.0 during 60 days under the acid rain treatment.The results indicated that the treatment of spaying with simulated acid rain pH 5.0 could increase leaf photosynthetic capacity.Meanwhile the treatment of spaying with simulated acid rain pH 3.0 and pH 2.0 would decrease photosynthesis capacity and also affect plants＇ growth.