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采用Li-6400便携式光合作用测定仪对3种南亚热带植物:变叶树参(Dendropanax proteu)、半枫荷(Semiliquidambar cathayensis)、台湾榕(Ficus formosana)幼树光合生理特性进行研究。结果表明:13种幼树的净光合速率(Pn)日变化均呈“双峰”曲线,变叶树参首峰(3.62μmol·m~(-2)·s~(-1))出现于10∶00,次峰(2.09μmol·m~(-2)·s~(-1))出现在16∶00;半枫荷首峰(3.15μmol·m~(-2)·s~(-1))出现于10∶00,次峰(1.75)出现在16∶00左右;台湾榕首峰(4.07μmol·m~(-2)·s~(-1))出现在9∶00左右,次峰(2.20μmol·m~(-2)·s~(-1))出现在16∶00左右。均具有明显的光合午休现象。2相关、回归及通径分析表明,3种植物Pn与光合有效辐射(PAR)、气孔导度(Gs)显著正相关,而与胞间CO2浓度(Ci)显著负相关,光合午休现象的原因很可能是环境因子变化引起叶肉细胞光合活性降低的非气孔限制因素。33种植物的光饱和点(LSP)、光补偿点(LCP)均较低,变叶树参分别为640.45、4.16μmol·m~(-2)·s~(-1);半枫荷分别为597.96、2.09μmol·m~(-2)·s~(-1);台湾榕分别为657.85、3.08μmol·m~(-2)·s~(-1),均为典型的阴生植物。
The photosynthetic characteristics of three southern subtropical plants: Dendropanax proteu, Semiliquidambar cathayensis and Ficus formosana were studied using Li-6400 portable photosynthesis analyzer. The results showed that the diurnal changes of net photosynthetic rate (Pn) of 13 young saplings showed “double peak” curve, the highest peak of 3.65μmol · m -2 · s -1 (-1) Appeared at 10:00 and the second peak (2.09μmol · m -2 · s -1) appeared at 16:00. The peak of half Fengfenghe (3.15μmol · m -2 · s ~ (-1)) occurred at 10:00 and the second peak (1.75) appeared at around 16:00. The first peak of Taiwan’s Rongzhou (4.07μmol · m -2 · s -1) appeared at 9:00 The second peak (2.20μmol · m -2 (-2) · s -1) appeared around 16:00. All photosynthetic midday have obvious phenomenon. Correlation, regression and path analysis showed that there was a significant positive correlation between Pn and photosynthetically active radiation (PAR) and stomatal conductance (Gs), but negatively correlated with intercellular CO2 concentration (Ci) It is likely that non-stomatal limitation of mesophyll cell photosynthetic activity caused by changes of environmental factors. The light saturation points (LSPs) and light compensation points (LCPs) of 33 species of plants were all lower, with the values of 640.45 and 4.16μmol · m -2 · s -1 respectively. Were 597.96 and 2.09μmol · m -2 · s -1, respectively, and the results were as follows: .