Silvicultural and ecophysiological research on the responses of regenerated tree seedlings to high CO_2 and sun fleck under forest floor condition

在寒温带森林地面，CO_2浓度有时可达600ppm，水分胁迫对幼苗存活是中等的。随着森林结构的发展，幼苗可以有效地利用高CO_2的阳光。研究了常绿灌木竹材莎莎（Sasa）和夏季落叶灌木达芙妮（Daphne）光合特性与光利用能力的关系。这些光合速率在早春和早秋打开冠层时增加。耐阴品种的光合诱导时间短于光强品种。光照强度的增加使白蜡和卡洛帕加幼苗分枝增加，在光照条件下增加20%以上。

In cool temperate forest floor, CO_2 concentration sometimes reaches to 600ppm and water stress is moderate for seedling survival. With development of forest structure, seedlings can efficiently use of sunlight with high CO_2. Photosynthetic characteristics of Sasa (an evergreen shrub bamboo) and Daphne (summer deciduous shrub) was studied in relation to light utilization capacity. These photosynthetic rate increased when top canopy was open in early spring and autumn. Photosynthetic induction time of shade tolerant species was shorter than that of light demanding seedlings. Branching of ash and kalopanax seedlings increased with increasing light intensities more than 20 % against open condition.