5个引种美国红枫品种的光合特性比较

Comparative Study on Photosynthetic Characteristics of Five Introduced Varieties of Acer rubrum

对5个引种美国红枫品种净光合速率(Pn)日变化、有效光辐射(PAR)和CO_2响应比较分析。结果表明:‘白兰地’和‘冷峻’Pn日变化曲线呈非典型双峰型,二者光合效率和蒸腾速率较高,说明它们在强光下光合效率较高;‘阿姆斯特朗’、‘夕阳红’和‘卓越’Pn日变化曲线呈典型双峰型,具有明显的午休现象,水分缺失影响美国红枫光合日变化,因此日常管护要注意及时灌溉补水。光响应曲线和CO_2响应曲线数据分析表明:‘白兰地’和‘冷峻’光饱和点(1 066.80、1 037.41μmol·m^(-2)·s^(-1))、CO_2饱和点(1 209.21、1 116.78μmol·m^(-2)·s^(-1))均高于其它三个品种,说明它们对强光的适应性好;‘阿姆斯特朗’和‘夕阳红’光呼吸(6.150 7、6.719 9μmol·m^(-2)·s^(-1))强于其它三个品种,是它们适应强光的一种保护机制。5个引种美国红枫品种中‘冷峻’、‘白兰地’对强光适应性好生长迅速,‘阿姆斯特朗’、‘夕阳红’和‘卓越’在栽培管护中应适当遮阴以促进生长。

The diurnal changes of photosynthesis,light response curves and CO_2 response curves of five Acer rubrum varieties were compared and analyzed. The results showed that the diurnal changes of the net photosynthetic rate（ Pn） of Brandy and Acer × freemanii Marmo displayed not typical double-peak curve,and their transpiration rate and photosynthetic efficiency were higher indicating their higher photosynthetic efficiency under strong light. The diurnal changes of Pn of Armstrong,Red Sunset and Somerset displayed typical double-peak curve,so they had obvious midday depression. The diurnal changes of Pn of Acer rubrum was influenced by water deficit significantly,so the daily management should pay more attention to irrigation timely. The analysis of light response curve and CO_2 response curve showed that both the light saturation point（ 1 066. 80 and 1 037. 41 μmol·m^（-2）·s^（-1）） and the saturation intercellular CO_2 concentration（ 1 209. 21 and 1 116. 78 μmol·mol^（-1）） of Brandy and Acer × freemanii Marmo were higher than those of the other three varieties,which showed better adaptability to bright light. The rate of photorespiration（ 6. 1507 and 6. 7199μmol·m^（-2）·s^（-1）） of Armstrong and Red Sunset were better than that of the other three varieties,which is a protective mechanism for them adapt to bright light. Among the five Acer rubrum,Acer × freemanii Marmo andBrandywine had better adaptability to bright light and grew faster; Armstrong,Red Sunset and Somerset needed shade protection to promote their growth.