【摘要】 高山林线对于气候变化的影响非常敏感。气候变化首先从个体的水平影响林线的内部结构 ,然后才影响到作为整体的林线的推移 ,因此研究乔木个体生理活动与气候条件之间的关系 ,对于研究高山林线对气候变化的响应具有重要意义。本文通过对位于中国东部暖温带的五台山、关帝山、太白山森林上限附近白杆 (Piceameyeri)、华北落叶松 (Larixprincipis-ruprechtii)和太白红杉 (L .chinensis)生理活动与环境因子的野外测定 ,分析了光合作用与环境因子之间的关系 ,得出以下初步结论 :(1)研究区内林线乔木的光合作用不存在单一的限制因子 ;(2 )有关研究表明 ,光照与温度共同作用于高山林线乔木的光合作用 ,在光照较低的情况下 ,温度成为光合作用的限制因子 ,本研究进一步证实了这一现象 ;(3)树线、林缘、郁闭林内三种不同生境条件下乔木光合作用的对比表明 ,林缘的生境条件最适合植物光合作用。虽然林缘的湿度条件中等 ,但良好的光照和温度条件对光合作用有促进作用更多还原

【Abstract】 Alpine timberline is very sensitive to climatic changes.The changing climate first affects the structure of alpine timberline at an autecological level, and further affects the movement of the timberline as a whole.The relationships between physiological activities of alpine trees and climatic conditions are thus important to the studies on the response of alpine timberline to climatic changes.After measurements of physiological activities and environmental factors of timberline trees, including Picea meyeri and Larix principis-ruprechtii on Mt.Wutai, L.principis-ruprechtii on Mt.Guandi and L.chinensis on Mt.Taibai, the relationships between net photosynthesis and environmental factors are made to draw the following conclusions:(1) Limit factors for photosynthesis are different on these three mountains under different climatic conditions;(2)It is demonstrated that PAR and air temperature are combined to affect photosynthesis, temperature becomes the limit factor of photosynthesis when the PAR is low, our results verify this conclusion; (3) A comparison of photosynthesis among tree line, forest edge and forest interior shows that the habitat of forest edge is most favorable for photosynthesis.Although humidity conditions is medium, the good radiation and temperature conditions there are beneficial for photosynthesis.更多还原