连翘叶片光合速率日变化特征的研究

Diurnal variations of photosynthesis in leaves of Forsythia suspense

采用Li-6400便携式全自动光合测定仪对连翘叶片光合速率及其相关因子的日变化规律进行测定。结果表明:在晴朗无风条件下,连翘光合速率(Pn)日变化呈单峰曲线,峰值出现在上午12:00时,为13.27μmol CO_2.m^(-2).s^(-1);蒸腾速率(Tr)的日变化也为一单峰曲线,峰值也出现在12:00时,为3.38μmo H_2O.m^(-2).s^(-2)。影响连翘叶片净光合速率日变化的主要生理因子是气孔导度、蒸腾速率和胞间CO_2浓度,主要生态因子是光合有效辐射和相对湿度等。采用相关分析和多元逐步回归分析方法,得出光合速率和蒸腾速率与大气CO_2浓度、胞间CO_2浓度、大气温度等生理生态因子间的相关关系,并建立了相应的影响因子回归方程,相关系数可达0.999999。

Diurnal Variations of net photosynthetic rate （Pn） and its affecting environmental factors of Forsythia suspensa were measured by using the Li-6400 portable photosynthesis system .The results indicated that in the typical sunny days, the curve of diurnal variation of net photosynthetic rate （Pn） was one-peak curve. And the peak value was13.27μmol·m-2·s-1, which occurred at 12：00 oc＇ lock in the morning. The curve of diurnal variation of transpiration rate was also one-peaked, and the peak value was also 3.38μmol·m-2·s-1, which occurred at 12：00 oc＇ lock in the morning. The main physiological factors that affect diurnal variation of Pn include stomatal conductance, intercellular CO2 concentration and transpiration ;and the main environmental factors, light intensity and relative humidity. By themethods of correlation analysis and stepwise multi-regression analysis, the correlations between them and environ-mental factorswere assessed. The related equation were also constructed in this paper, and correlation coefficients were 0.999999, respectively.