用CIRAS-2 便携式光合测定系统测定了9 月至10 月10 个秋菊[Dendranthema morifolium (Ramat.) Tvzel.]品种叶片的光合特征参数;在此基础上,对叶片光响应参数和CO2 响应参数以及部分光合特征参数的日变化进行了比较分析;此外,还对净光合速率(Pn)与部分生理生态因子的相关性进行了分析。结果表明:10 个秋菊品种的光补偿点(LCP)为92. 83 ~167. 37 μmol ·m^-2 ·s^-1 ,光饱和点(LSP)为962. 51 ~1 077. 53 μmol ·m^-2 ·s^-1 ,说明它们均为喜光植物;10 个秋菊品种的CO2 饱和点为1 060. 46 ~ 1 485. 48 μmol · mol^-1 ,CO₂ 补偿点为77. 62 ~ 133. 16μmol · mol^-1 ,远大于一般的C3 植物;各品种Pn 的日变化呈典型的双峰型曲线,首峰(11 ~19 μmol·m^-2 ·s^-1 )出现在10:00 左右,次峰出现在16:00 左右,有明显的“午休”现象。相关分析结果表明:10 个品种的Pn 与气孔导度呈极显著正相关,与蒸腾速率呈显著或极显著正相关(品种‘关东新侠’、‘云龙凤舞’和‘日本黄’除外),与胞间CO₂浓度呈显著或极显著负相关,与光合有效辐射强度和大气温度呈不显著正相关,与大气相对湿度和大气CO₂ 浓度呈不显著负相关。早花品种‘太平的小鼓’和‘铜雀春深’具有较高的LSP 以及较低的LCP 和表观量子效率(AQY),对光照强度的适应范围较大,可栽培在光照较强的环境中;品种‘早粉盘’和‘檀香狮子’具有较高的LCP、AQY 和LSP,对强光的利用能力较强;晚花品种‘关东新侠’、‘绿牡丹’和‘星光灿烂’具有较高的LCP 和AQY 以及较低的LSP,具有一定的耐阴能力,可种植在光照较弱的环境中。

Parameters of photosynthetic characteristics of leaves of ten cultivars of autumn chrysanthemum [Dendranthema morifolium (Ramat.) Tvzel.]from September to October were determined by CIRAS-2 portable photosynthesis system. On this basis, light and CO₂ response parameters and daily change of parameters of some photosynthetic characteristics were analyzed comparatively, and the correlation between net photosynthetic rate (Pn) and some physio-ecological factors was also analyzed. The results show that light compensation point (LCP) of ten cultivars is 92. 83-167. 37 μmol ·m^-2 ·s^-1 and light saturation point (LSP) is 962. 51-1 077. 53 μmol ·m^-2·s^-1, meaning that they are heliophyte. Their CO₂ saturation point is 1 060. 46-1 485. 48 μmol · mol^-1 and CO₂ compensation point is 77. 62-133. 16 μmol · mol-1, which are extremely higher than those of normal C3-plants. The daily change curve of Pn of ten cultivars is a typical double peak type curve, the first peak (11-19μmol·m^-2 ·s^-1 ) and the second peak appear at about 10: 00 and 16: 00, respectively, and there is obvious “midday depression” phenomenon. The results of correlation analysis show that Pn very significantly positively correlates with stomatal conductance, significantly or very significantly positively correlates with transpiration rate (except cultivars ‘Guandongxinxia’, ‘Yunlongfengwu’ and ‘ Ribenhuang’) , significantly or very significantly negatively correlates with intercellular CO₂ concentration, and un-significantly positive correlates with photosynthetically active radiation intensity and atmospheric temperature, un-significantly negative correlates with atmospheric relative humidity and atmospheric CO₂ concentration. Early flowering cultivars ‘Taipingdexiaogu’and ‘Tongquechunshen’ possess higher LSP and lower LCP and apparent quantum yield (AQY), indicating that both of them can adapt to wider light intensity and are suitable to be planted in stronger light intensity environment. While cultivars ‘Zaofenpan’ and  ‘Tanxiangshizi’ possess higher LCP, AQY and LSP, indicating that they have stronger ability to use strong light intensity. Late flowering cultivars ‘Guandongxinxia’, ‘Lümudan’and ‘Xingguancanlan’ all possess higher LCP and AQY and lower LSP, indicating that they have certain shade tolerance and can be planted in weaker light intensity environment.