典型城区与郊区环境下大叶黄杨光合特性的比较

Comparative Analysis on Photosynthetic Characteristics of Euymus Japinicus Thunb in Typical Urban and Suburban Environment

应用Li-6400便携式光合作用测定系统于2007年8~10月对北京典型城区环境与郊区环境下大叶黄杨的光合特性进行了比较研究。城区环境相对于郊区环境,大叶黄杨的胞间CO2浓度、叶面水气压亏缺、蒸腾速率较高,水分利用效率、光能利用效率、CO2利用效率、气孔导度较低,净光合速率却有一定程度的降低。采用多元逐步回归的统计分析方法,得出了不同环境下净光合速率与气孔导度、胞间CO2浓度、叶面水气压亏缺、光合有效辐射、气温、相对湿度的关系方程。不同月份两个样点大叶黄杨净光合速率的主要影响因子都不相同,总的来看,气孔导度、胞间CO2浓度、温度和湿度状况影响着净光合速率的变化,城区环境下大叶黄杨同化CO2的能力降低。

A comparative experimental research on the leaf photosynthetic characteristics of Euymus japinicus Thunb trees growing in the typical urban and suburban plots was conducted in August,September and October in 2007 by using Li-6400 portable photosynthesis system.The results showed that the indicators of intercellular CO2,Vpdl and transpiration rate in Euymus japinicus Thunb at the urban plot were higher than that at the suburban plot,and water use efficiency,light use efficiency,CO2 use efficiency and stomatal conductance in Euymus japinicus Thunb at the urban plot were lower than that at the suburban plot.There was not any significant difference at the net photosynthetic rate between the two sampling plots in August and September,and the net photosynthetic rate became lower at the urban plot than that at the suburban plot in October.Moreover,the major environmental factors affecting the indicator of net photosynthetic rate in Euymus japinicus Thunb was also analyzed by using multivariate step-wise regression.There were obviously different at the two sampling plots for some indicators which included stomatal conductance,intercellular CO2,temperature and humidity,and the CO2 assimilation capacity in Euymus japinicus Thunb became lower at the urban plot than that at the suburban plot from August to October.