玄参光合日变化特征的研究

目的]研究玄参净光合速率的日变化特性,为玄参栽培提供参考。方法]利用Li-6400便携式光合作用系统测定不同时段、不同光合有效辐射下的净光合速率,以及环境因子对光合速率日变化的影响。结果]玄参的光响应曲线为一单峰曲线,玄参光饱和点为1 624μmol/(m2.s);光补偿点为21.16μmol/(m2.s)。净光合速率日变化呈双峰曲线,有典型的"午休"现象。经相关性分析,净光合速率与光合有效辐射、蒸腾速率、气孔导度、温度之间呈正相关,与胞间CO2浓度呈负相关,与相对湿度的相关性不显著。结论]玄参为阳生植物,气孔导度、光合有效辐射和蒸腾速率是影响玄参叶片净光合速率的主要环境因子。

Study on the Diurnal Variation of Photosynthetic Characteristics of Scrophularia ningpocnsis Hemsl

Objective] The purpose was to study the diurnal variation characteristics of the net photosynthetic rate of Scrophularia ningpoensis Hemsl.and provide reference for the cultivation of S.ningpoensis.Method] By using Li-6400 portable photosynthesis system,the net photosynthetic rate under different photosynthetically active radiation at different periods and the effects of environmental factors on the diurnal variation of photosynthetic rate were determined.Result] The light response curve of S.ningpoensis was a single peak curve,the light saturation point and light compensation point of S.ningpoensis were 1 624 and 21.16 μmol/(m2·s) respectively.The diurnal variation of net photosynthetic rate showed a double peak curve and had the typical 'midday depression' phenomenon.The correlation analysis showed that net photosynthetic rate of S.ningpoensis had positive correlations with photosynthetically active radiation,transpiration rate, stomatal conductance and temperature,and it had a negative correlation with intercellular CO2 concentration.Its correlation with the relative humidity was not significant.Conclusion] S.ningpoensis is a kind of heliophyte.The stomatal conductance,photosynthetically active radiation and transpiration rate are main environmental factors that affect the net photosynthetic rate of S.ningpoensis leaves.