水杉林下构树与槐树的光合特性研究

The Photosynthetic Characteristics of Broussonetia kazinoki and Sophora japonica L.in Forest of Metasequoia glyptostroboides

采用Li-6400便携式光合仪,对上海南汇区水杉基干林带林下阔叶树种构树、槐树的光合特性进行了测定,结果表明:(1)两种植物光合日变化曲线均为单峰曲线,未出现光合午休现象,达到峰值后光合速率下降的影响因素是气孔限制;(2)水分利用率日均值为槐树(2.56)>构树(0.91);(3)环境因子中,光照和大气相对湿度是影响净光合速率的重要因子。两个树种对水杉林下复杂的生态环境有一定的适应性。

By using Li-6400 portabl e photosynthesis system, we observed the photosynthetic characteristics of Broussonetia kazinoki and Sophorajaponica L. in the backbone forest of Metasequoia glyptostroboides in Nanhui district of Shanghai. The results showed that： （1） Daily change of the two species all showed single-peak curve, and did not appear midday depression of photosynthesis; the stomatal limitation caused the decline of photosynthetic rate after reaching the peak value. （2） Daily average value of water use efficiency of Sophorajaponica L. （2.56） was higher than that of Broussonetia kazinoki （0.91）. （3） Light and atmospheric relative humidity were important factors which to influence the net photosynthesis rate among environmental factors. These two species owned certain adaptability to the complex ecological environment in forest of Metasequoia glyptostroboides.