8种园林树种光合作用特征与水分利用效率比较

The Photosynthesis and Water Use Efficiency of Eight Garden Tree Species

以光合蒸腾测定系统测定了夏季生长期内 8种 2 3年生园林树种叶片气体交换特征参数的日变化。结果如下 :(1)净光合速率 (Pn)、气孔导度 (gs)、蒸腾速率 (E)、水分利用效率 (WUE)日变化明显 ,且存在明显的种间差异。 (2 )净光合速率日均值 (μmol·m- 2 ·s- 1)依次为鸡冠刺桐 (11.2 ) >水翁(9.7)、印度紫檀 (8.6 )、柳叶垂榕 (8.5 ) >假苹婆 (6 .3) >水瓜栗 (5 .8)、南洋樱花 (5 .6 ) >中国无忧树(3.4 ) ,前 4个树种固定CO2 的能力高于其它树种。 (3)蒸腾速率 (mmol·m- 2 ·s- 1)日均值分别是鸡冠刺桐 (3.4 0 ) >柳叶垂榕 (2 .79) >水翁 (2 .5 5 ) >假苹婆 (2 .32 )、水瓜栗 (2 .32 ) >中国无忧树 (2 .2 5 )、印度紫檀 (2 .2 5 ) >南洋樱花 (1.5 7) ,前 3个树种比其它树种消耗更多的水分。 (4)印度紫檀、水翁、南洋樱花和鸡冠刺桐具有较高的水分利用效率 ,分别是 3.97、3.73、3.6 8、3.4 8和 3.84 μmolCO2 ·mmol- 1H2 O ,而柳叶垂榕、假苹婆、水瓜栗、中国无忧树的水分利用效率相对较低 ,分别为 3.0 3、2 .79、2 .6 4和2 .5 μmolCO2 ·mmol- 1H2 O ,表明消耗等量的水分前 4个树种比其它 4个树种能够固定更多数量的CO2 ,即能够更有效地利用土壤水分。这些信息有助于解释不同树种在生长速度。

Gas exchange parameters in leaves of eight 2 to 3 year old garden tree species growing in the institute nursery were measured during the summer in 1999, by using LCA 4 portable photosynthesis and transpiration system. The results are as follows: (1) the daily variation of the net photosynthesis rate( P n , μmol·m -2 ·s -1 ), stomatal conductance(g s, mol·m -2 ·s -1 ), transpiration rate( E , mmol·m -2 ·s -1 ), and instantaneous water use efficiency(Pn/E, μmol CO 2·mmol -1 H 2O) are remarkable and differ among species. (2) the daily average P n are 11.2, 9.7, 8.6, 8.5, 6.3, 5.8, 5.6 and 3.4 μmol·m -2 ·s -1 for Erythrina crista galli, Cleistocalyx operculata, Pterocarpus indicus, Ficus celebensis, Sterculia lanceolata, Pachira aquatica, Jatropha pandurifolia, Saraca dives pierre,respectively, showing that the first four species have relatively higher capacity for CO 2 assimilation. (3) the daily mean values of transpiration rate are 3.40, 2.79, 2.55, 2.32, 2.32, 2.25, 2.25 and 1.57 mmol·m -2 ·s -1 for Erythrina crista galli, Ficus celebensis, Cleistocalyx operculata, Sterculia lanceolata, Pachira aquatica, Saraca dives pierre, Pterocarpus indicus, Jatropha pandurifolia , respectively, indicating that the former 3 species consume greater amount of water than other species. (4) The daily average WUE are 3.97, 3.73 , 3.68, 3.48, 3.84, 3.03, 2.79, 2.64 and 2.50 μmol CO 2·mmol -1 H 2O for Pterocarpus indicus, Cleistocalyx operculata , Jatropha pandurifolia , Erythrina crista galli , Ficus celebensis, Sterculia lanceolata, Pachira aquatica , Saraca dives pierre, respectively,suggesting that the first four species have relatively higher water use efficiency than the others. Information presented here is helpful for understanding the differences among species in aspects of growing and productivity. It might also be useful to guide garden practices in water management.