Abstract: This study investigated six common garden shrubs (Ficus benjamina, Fagraea ceilanica, Ficus microcarpa 'Golden Leaves', Ixora chinensis, Allamanda cathartica, and Heptapleurum heptaphyllum) in Bihu Park, Zhangzhou City. By measuring light response curves, chlorophyll content, and gas exchange parameters, the differences in their photosynthetic characteristics and carbon sequestration-oxygen release capacity were systematically analyzed. The results showed that the total chlorophyll content of Ficus benjamina, Allamanda cathartica, and Ixora chinensis was significantly higher than those of Fagraea ceilanica, Ficus microcarpa 'Golden Leaves', and Heptapleurum heptaphyllum (P＜0.05). The diurnal variation of net photosynthetic rate (P_n) in Ficus microcarpa 'Golden Leaves', Ixora chinensis, and Ficus benjamina exhibited an "increase-decrease" trend, whereas Allamanda cathartica and Fagraea ceilanica showed a continuous decline in P_n. With increasing photosynthetically active radiation (PAR), stomatal conductance (G_s) and transpiration rate (T_r) generally rose. Significant differences (P＜0.05) were observed in daily net assimilation, carbon sequestration, and oxygen release per unit leaf area among the six plants. Ficus benjamina performed the best (daily net assimilation 181.254 mmol·m^–2·s^–1; carbon sequestration 6.374 g·m^–2·d^–1; oxygen release 4.639 g·m^–2·d^–1), while Fagraea ceilanica was the weakest. Light response curve fitting revealed that Ixora chinensis had the highest light saturation point (LSP, 1592.633 μmol·m^–2·s^–1), and Heptapleurum heptaphyllum exhibited significantly lower light compensation points (LCP) than other species, demonstrating better adaptability to low light. Allamanda cathartica had the highest maximum net photosynthetic rate (7.38 μmol·m^–2·s^–1) and dark respiration rate (3.588 μmol·m^–2·s^–1). Considering photosynthetic and carbon sequestration characteristics, it is recommended to prioritize shrubs with high light energy utilization efficiency, such as Ficus benjamina and Ixora chinensis, in urban greening to enhance carbon-oxygen balance regulation.

Key words: photosynthetic characteristics, carbon sequestration-oxygen release, garden shrubs, chlorophyll

摘要： 以漳州市碧湖公园垂叶榕Ficus benjamina、灰莉Fagraea ceilanica、黄金榕Ficus microcarpa 'Golden Leaves'、龙船花Ixora chinensis、软枝黄蝉Allamanda cathartica、鸭脚木Heptapleurum heptaphyllum等6种常见园林灌木为试材，通过测定叶片光响应曲线、叶绿素含量及气体交换参数，系统研究其光合特性与固碳释氧能力差异。结果表明，垂叶榕、软枝黄蝉、龙船花的总叶绿素含量显著高于灰莉、黄金榕和鸭脚木(P＜0.05)；黄金榕、龙船花、垂叶榕净光合速率(P_n)日变化呈上升–下降趋势，软枝黄蝉和灰莉P_n呈持续下降趋势；随光合有效辐射(PAR)增加，气孔导度(G_s)和蒸腾速率(T_r)总体呈上升趋势。6种植物单位叶面积日净同化量、固碳量和释氧量差异显著(P＜0.05)，垂叶榕均表现最优(日净同化量181.254 mmol·m^–2·s^–1、固碳量6.374 g·m^–2·d^–1、释氧量4.639 g·m^–2·d^–1)，灰莉最弱。光响应曲线拟合显示，龙船花光饱和点(LSP)最高(1592.633 μmol·m^–2·s^–1)，强光利用能力最强，灰莉、鸭脚木的光补偿点(LCP)显著低于其他种类，表现出较好的弱光适应性；软枝黄蝉最大净光合速率(7.38 μmol·m^–2·s^–1)和暗呼吸速率(3.588 μmol·m^–2·s^–1)均较高。综合考虑植物光合与固碳特性，在树种配置时，建议优先选用垂叶榕、龙船花等高光能利用效率灌木，以提升城市绿化的碳氧平衡调节功能。

关键词: 光合特性, 固碳释氧, 园林灌木, 叶绿素