对半蒴苣苔属(Hemiboea C. B. Clarke)植物半蒴苣苔(H. henryi C. B. Clarke)、贵州半蒴苣苔(H. cavaleriei H. Lév.)、疏脉半蒴苣苔(H. cavaleriei var. paucinervis W. T. Wang et Z. Y. Li ex Z. Y. Li)、华南半蒴苣苔(H. follicularis C. B. Clarke)和红苞半蒴苣苔(H. rubribracteata Z. Y. Li et Yan Liu)叶片的光合特性进行了分析和比较。结果表明:5 种植物的光合参数及其日变化曲线、光响应参数[(包括最大净光合速率(Pmax )、表观量子效率(AQY)、光补偿点(LCP)和光饱和点(LSP))、CO₂ 响应参数[包括CO₂ 饱和净光合速率(CSPn)、羧化效率(CE)、CO₂ 补偿点(CCP)和CO₂ 饱和点(CSP)]均有较大差异。半蒴苣苔、疏脉半蒴苣苔和红苞半蒴苣苔的净光合速率(Pn)日变化曲线均呈“单峰型”,而贵州半蒴苣苔和华南半蒴苣苔的Pn 日变化曲线均呈“双峰型”且“午休”现象明显;贵州半蒴苣苔和疏脉半蒴苣苔的气孔导度(Gs)和蒸腾速率(Tr)日变化曲线均呈“单峰型”,而其他3 种植物的Gs 和Tr 日变化曲线均类似“双峰型”;5 种植物的胞间CO₂ 浓度(Ci)日变化均呈先降后升的趋势;此外,5 种植物的Pn 与Gs 均呈显著正相关、与Tr 均呈正相关、与Ci 均呈负相关。5 种植物的光响应曲线和CO₂ 响应曲线均有差异,但在光合有效辐射(PAR)低于200 μmol·m^-2 ·s^-1 或环境CO₂ 浓度(Ce)低于800 μmol·mol^-1 的条件下,它们的Pn均随PAR 或Ce 的升高急剧增加。5 种植物中,贵州半蒴苣苔的Pmax最高,疏脉半蒴苣苔的CSPn 最高;贵州半蒴苣苔的LCP 最高(55. 74 μmol·m^-2 ·s^-1 ),其他4 种的LCP 均小于10 μmol·m^-2 ·s^-1 ;5 种植物的LSP 均介于600 ~800 μmol·m^-2 ·s^-1 之间,CCP 介于50 ~ 150 μmol·mol^-1 之间,而CSP 均在1 000 μmol·mol^-1 以上。研究结果揭示:供试5 种植物均为阴生植物,但因产地生境及遗传特性差异使它们各自适应不同的光照条件,因而,在引种栽培过程中应根据各种类的光合特性采取适当的遮阳措施。

The photosynthetic characteristics of leaf of five species in Hemiboea C. B. Clarke including H. henryi C. B. Clarke, H. cavaleriei H. Lév., H. cavaleriei var. paucinervis W. T. Wang et Z. Y. Li ex Z. Y. Li, H. follicularis C. B. Clarke and H. rubribracteata Z. Y. Li et Yan Liu were analyzed and compared. The results show that there are greater differences in photosynthetic parameters and their diurnal change curves, light response parameters including the maximum net photosynthetic rate (Pmax), apparent quantum yield (AQY), light compensation point (LCP) and light saturation point (LSP), and CO₂ response parameters including CO₂ saturated net photosynthetic rate ( CSPn), carboxylation efficiency (CE), CO₂ compensation point (CCP) and CO₂ saturation point (CSP) of five species. Diurnal change curves of net photosynthetic rate (Pn) of H. henryi, H. cavaleriei var. paucinervis and H. rubribracteata all are “single-peak” type, while those of H. cavaleriei and H. follicularis are “double- peak”type with obvious “ midday depression” phenomenon; diurnal change curves of stomatal conductance (Gs) and transpiration rate (Tr) of H. cavaleriei and H. cavaleriei var. paucinervis are “single-peak” type, while those of other three species are similar to “double-peak” type; diurnal change curves of intercellular CO₂ concentration (Ci) all appear a trend of firstly decreasing and then increasing. Moreover, Pn of five species has a significantly positive correlation with Gs, a positive correlation with Tr and a negative correlation with Ci. There are a certain differences in light response curves and CO₂ response curves of five species, but under conditions of photosynthetic active radiation (PAR) below 200 μmol·m^-1·s^-1or environment CO₂ concentration (Ce) below 800 μmol·mol^-1, Pn of five species all dramatically increases with enhancing of PAR or Ce. In five species, Pmax of H. cavaleriei is the highest and CSPn of H. cavaleriei var. paucinervis is the highest; LCP of H . cavaleriei is the highest (55. 74 μmol·m^-1·s^-1), while that of other four species is less than 10 μmol·m^-1·s^-1; LSP of five species is in 600 - 800 μmol·m^-2·s^-1, their CCP is in 50 - 150 μmol·mol^-1, and their CSP is above 1 000 μmol·mol^-1. It is suggested that all of five species tested are sciophyte, but they are suitable for different light conditions because of differences in location habitat and genetic characteristics, therefore, feasible shading measures should be taken in process of introduction and cultivation according to photosynthetic characteristics of each species.