海南重楼为濒危保护植物,野生资源匮乏,在引种后的人工栽培过程中,为向其提供良好的生长条件,充分发挥其光合潜力,需要了解其光合特性。以林下生长的海南重楼为材料,使用LI-6400XT便携式光合仪对其光合作用日变化、光响应特性及CO₂响应特性进行测量。海南重楼叶片净光合速率日变化表现为“单峰”曲线,峰值出现在14:00。相关分析和多元逐步回归分析发现,影响海南重楼净光合速率日变化的主要因子为气孔导度。海南重楼的光补偿点为3.04 μmol/(m²·s),光饱和点为737.5 μmol/(m²·s),表观量子效率为0.0452 μmol/(m²·s);海南重楼的CO₂补偿点为92.33 μmol/mol,CO₂饱和点为1687.5 μmol/mol,羧化速率为0.0124 μmol/mol。测量海南重楼的光合特性,可为其人工栽培的光照条件控制提供参考数据。

Paris dunniana is a kind of endangered and conservational plant with scarce wild resources. In the artificial cultivation process after P. dunniana introduction, to provide good growth conditions and give full play to its photosynthetic potential, it is necessary to understand P. dunniana photosynthetic characteristics and the relationship between physiological and ecological factors and photosynthetic rate. The diurnal variation of photosynthesis, light-response curve and CO₂-response curve of P. dunniana were studied using LI-6400XT portable photosynthesis system in closed stand. The diurnal variation of photosynthesis presented a single-peak curve, and its peak appeared at 14:00. The correlation analysis and multiple stepwise regression analysis showed that the main affecting factor of diurnal variation of photosynthesis was stomatal conductance (Cond). The light compensation point (LCP), light saturation point (LSP) and apparent quantum efficiency (AQY) were 3.04, 737.5 and 0.0452 μmol/(m²·s), respectively. The CO₂ compensation point (CCP), CO₂ saturation point (CSP), and carboxylation efficiency (CE) were 92.33, 1687.5 and 0.0124 μmol/mol, respectively. This experiment provides reference data for the control of light condition in the artificial cultivation of P. dunniana by measuring its photosynthetic characteristics.