菰叶片净光合速率日变化及其与环境因子的相互关系

Relationship Between Diurnal Changes of Net Photosynthetic Rate and Environmental Factors in Leaves of Zizania latifolia

【目的】通过研究菰叶片净光合速率日变化及其与环境因子的相互关系,目的为菰资源的开发和利用提供参考。【方法】利用Li-6400型光合作用测定系统,测定了菰叶片净光合速率和环境因子的日变化,通过相关性分析,考察了环境因子对净光合速率日变化的影响。【结果】菰功能叶片净光合速率为15.0～21.5μmol·m-2·s-1,光补偿点为45μmol·m-2·s-1,光饱和点为1040μmol·m-2·s-1。菰叶片净光合速率、气孔导度和蒸腾速率的日变化均呈单峰曲线,净光合速率的峰值出现在上午11:00时,上午8:00～11:00时的平均净光合速率比下午13:00-16:00时的平均净光合速率高4.7μmol·m-2·s-1。气孔导度和蒸腾速率的峰值分别出现在13:00和14:00时。一日中上午5:00～11:00和下午15:00～19:00时净光合速率与光量子通量密度之间呈显著正相关(r=0.9874**、0.9321**),11:00～15:00时两者之间呈不显著正相关(r=0.4440)。上午5:00～11:00和下午15:00～19:00时净光合速率与空气温度之间呈显著正相关(r=0.9617**、0.9852**),11:00～15:00时两者之间呈显著负相关(r=-0.8110*)。净光合速率与气孔导度之间呈正相关(r=0.7936*),与胞间CO2浓度呈负相关(r=-0.8026*)。气孔导度和蒸腾速率与光量子通量密度之间呈显著的正相关(r=0.9104**、0.7858*)。【结论】菰叶片的光补偿点较低,而光饱和点较高,对光环境的适应性较强,为典型的阳生植物。影响净光合速率日变化的主要环境因子是光量子通量密度和空气温度。

[ Objective ] Relationship between diurnal changes of net photosynthetic rate and environmental factors in leaves of Z. latifolia were studied. The results provided scientific basis for using resources of Zlatifolia. [Method] Diurnal changes of net photosynthetic rate and environmental factors in leaves of Zlatifolia were measured using Li-6400 portable photosynthesis system. The relationship between net photosynthetic rate and environmental factors were analyzed by correlation analysis. [ Result] The net photosynthetic rate was in the range of 15.0-21.5 μmol·m^-2·s^-1 in un-folding leaves of Zlatifolia. Light compensation point of photosynthesis of Z.latifolia in un-folding leaves was 45 μmol·m^-2·s^-1. Light saturation point of photosynthesis was 1 040 μmol·m^-2·s^-1 Diurnal changes of the net photosynthetic rate, stomatal conductance and transpiration rate were all one-peak curve in leaves of Z.latifolia. The peak of net photosynthetic rate was measured at 11：00 a.m., the average net photosynthetic rate in leaves of Z.latifolia at 8：00-11：00 was higher 4.7 μmol·m^-2·s^-1 than at 13：00 16：00. The peaks of stomatal conductance and transpiration rate were measured at 13：00 and 14：00 p.m. During a day, the net photosynthetic rate was significantly positively correlated with photo flux density （PFD） at 5：00-11：00 a.m. and 15：00-19：00 p.m. Correlation coefficient were 0.9874＊＊ and 0.9321＊＊, respectively. The net photosynthetic rate showed little positive correlation with PFD at 11：00-15：00. The correlation coefficient was 0.4440. The net photosynthetic rate showed significantly positively correlated with temperature at 5：00-11：00 a.m. and 15：00-19：00 p.m. The correlation coefficients were 0.9617＊＊ and 0.9852＊＊, respectively. The net photosynthetic rate was significantly negatively correlated with temperature at 11：00-15：00. The correlation coefficient was -0.8110＊. The net photosynthetic rate was significantly positively correlated with stomatal conductance, and was significantly negatively correlated with intercellular CO2 concentration. The correlation coefficients were 0.7936＊ and -0.8026＊, respectively. Stomatal conductance and transpiration rate were significantly positively correlated with PFD. The correlation coefficients were 0.9104＊＊ and 0.7858＊, respectively. [Conclusion] Light compensation point of photosynthesis of Z.latifolia in un-folding leaves is lower, but light saturation point of photosynthesis is higher. Z.latifolia is adaptable widely to photo flux density and is a typical heliophyte. Photo flux density and air temperature are major environmental factors influencing diurnal changes of net photosynthetic rate.