银杏光合生理生态特性研究

该文于2006年5—10月，利用Li-6400便携式光合作用测定系统对北京市植物园银杏的生理生态特性进行研究，探讨银杏叶片光合作用和蒸腾作用的动态规律，并揭示其主要影响机理。结果表明:银杏叶片净光合速率在5—9月份呈典型的双峰曲线，有明显的“光合午休”现象，并在6月份出现年光合速率最大值；10月份光合速率呈单峰曲线。从整个生长季来看，光合有效辐射（PAR）、气孔导度（Gs）分别是影响叶片净光合速率（Pn）最重要的环境因子和生理因子。在5—9月份银杏蒸腾速率（Tr）日变化呈现双峰曲线，10月份呈单峰曲线；整个生长季（5—10月份）Tr与PAR、叶片大气水汽压亏缺（VpdL）、气孔限制值（Ls）的相关性均比较显著，说明叶片VpdL、Ls和PAR是影响银杏叶片蒸腾速率的主要因子。 

Photosynthetic physioecology characteristics of Ginkgo biloba

To understand the dynamic changes of photosynthesis and transpiration in Ginkgo biloba leaves and reveal main affecting factors, a field experiment was conducted in Beijing Botanical Garden in 2006 From May to October, several physioecology characteristics using a Li-6400 portable photosynthesis system were measured. The results showed that the photosynthetic rate of G. biloba presented a typical double peak curve from May to September. There was an obvious phenomenon of midday depression on photosynthesis. The photosynthetic rate reached the highest in June and presented a single peak curve in October. In the whole growing season, PAR and G_s were the most significant environmental and physiological factors influencing P_n of the leaves. The transpiration rate (T_r) of G. biloba presented a double peak curve from May to October and a single peak curve in October. The Tr is obviously related to PAR, VpdL and L_s, showing that VpdL, L_s and PAR are the main factors influencing the T_r of G. biloba.