显脉金花茶的光合生理特性研究

采用LI-6400便携式光合测定系统(Li-Cor Inc., USA)对显脉金花茶光合特性进行研究。结果表明：(1)在夏季，显脉金花茶叶片的P_n日变化呈单峰曲线，最高峰出现在中午11：00。其最大净光合速率（P_max）为3.81 μmol·m^-2·s^-1、光饱和点（LSP）为459.9 μmol·m^-2·s^-1、光补偿点（LCP）为6.9 μmol·m^-2·s^-1。显脉金花茶的光饱和点和光补偿点都比较低，表明其是一种阴生植物。（2）在控制光照强度和温度的条件下，CO₂浓度小于800 μmol·mol^-1，P_n几乎呈直线上升，升高CO₂浓度可使显脉金花茶的净高合速率增大，提高了叶片对光能的利用率。其叶片CO₂饱和点(CSP)大约在1 200 μmol·mol^-1左右，CO₂的补偿点（Г^*）为70.1 μmol·mol^-1，最大羧化速率（V_cmax）为17.5 μmol·m^-2·s^-1，最大电子传递速率（J_max）为40 μmol·m^-2·s^-1。

The Photosynthetic Characteristics of Camellia euphlebia

The photosynthetic characteristics of leaves in Camellia euphlebia were studied with LI-6400 (Li-Cor Inc., USA) portable photosynthesis system. The results showed that the diurnal changes of photosynthetic rate (P_n) in C. euphlebia exhibited a mono-peak style, and the maximum value of P_n appeared at 11:00 am in summer. The maximum photosynthetic rate（P_max）, light saturation point（LSP）, light compensation point（LCP）for the leaves of C. euphlebia were 3.81 μmol·m^-2·s^-1, 459.9 μmol·m^-2·s^-1 and 6.9 μmol·m^-2·s^-1, respectively. The light saturation and compensation point were very low, which indicated that C. euphlebia was a shade plant. Under the condition of optimum light intensity and temperature, the net photosynthetic rate of C. euphlebia increased linearly when the concentration of CO₂ enhanced from 50 μmol·mol^-1 to 800 μmol·mol^-1. Elevation of CO₂ concentration increased the P_n and the efficiency of ligh utilizing in C. euphlebia. The CO₂ saturation (CSP), compensation point（Г^*）, the maximum carboxylation rate （V_cmax）and maximum rate of electron transport（J_max） were about 1 200 μmol•mol^-1, 70.1 μmol·mol^-1, 17.5 μmol·m^-2·s^-1, respectively.