桂林岩溶区青冈栎光合速率与环境因子关系初步研究

Preliminary study on the relation between photosynthetic rate and environment factors of Quercus glauca in Guilin karst area

在自然条件下,对桂林岩溶区青冈栎光合速率与环境因子的关系研究表明,初夏季节青冈栎蒸腾速率日变化为"单峰"曲线,光合速率日变化为"双峰"型曲线,午间光合速率明显降低。青冈栎光合"午休"主要由气孔导度降低引起;通径分析表明,环境因子中空气相对湿度和空气温度对青冈栎光合速率直接影响最大;光合有效辐射对青冈栎光合速率直接影响不显著,而主要是通过其它因子间接影响光合速率。

The relation between photosynthetic rate（Pn）of Quercus glauca and environmental factors had been studied under natural condition in karst area.The results indicated that the curve of diurnal variation of transpiration was single-peaked,and Pn was dual-peaked with obvious midday depression in early summer.The midday depression of photosynthesis was principally caused by decline of stomatal conductance（Gs）.The path coefficient analysis showed that the air relative humidity and air temperature were the main environmental factors which direct influenced the Pn.Photosynthetically active radiation（PAR）had no significant directly influence to the Pn,but through other factors affect Pn indirectly.