边缘效应带促进红松生长的光合生理生态学研究

以一个经过12a边缘效应带处理的14年生红松幼林生态系统为研究对象，通过对3种宽度(4m，6m，8m)边缘效应带及保留带内红松幼树的光合日进程、碳素日积累量及相关生理生态学因子(光照、气孔导度、小枝木质部水势、叶片温度、叶面饱和蒸气压亏缺)的研究，探讨了造成不同效应带和保留带内红松生长差异的光合生理生态学原因。结果：4m效应带光照不足引起的碳素日积累量过低导致红松生长较差，8m效应带气孔导度过低引起的光合午休现象导致了碳素日积累量低、红松生长较差。8m效应带引起气孔导度下降的因素主要是过强光照引起叶片温度较高、叶面饱和蒸气压亏缺较大以及小枝木质部水势过低。研究认为，太宽的8m带和太窄的4m带都在一定程度上引起了光合生理生态学的不适应，导致生长水平下降，6m宽度的边缘效应带是人工促进红松生长的最佳边缘效应带。

Photosynthetic ecophysiological study on the growth of korean pine (Pinus koraiensis) afforested by the edge-effect belt method

A 14 year old Korean pine ( Pinus koraiensis ) forest (as of 1998), afforested after clear cutting of 4 m , 6 m and 8 m width edge effect belts in an oak ( Quercus mongolica) secondary forest in 1986 (with a 10 m width undisturbed belt close to each edge effect belts, namely reserved belts), was studied. In each edge effect belts and reserved belts, growth status parameters (basal diameter, canopy projection area) and diurnal course of net photosynthesis, daily carbon accumulation, and other ecophysiological parameters, such as photosynthetic active radiation, stomatal conductance, xylem water potential of current year branch, leaf temperature, vapor pressure deficit of leaf, were measured to discover the photosynthetic ecophysiological reason responsible for the growth differences in different treatment plots. The results indicate that the lower photosynthetic active radiation and subsequent lower carbon daily accumulation induced the lower potential of growth in the 4 m edge effect belt, while the lower stomatal conductance and subsequent photosynthesis noon depression and lower daily carbon accumulation induced the lower potential of growth in the 8 m edge effect belt. In comparison to the 4 m and 8 m edge effect belt, the 6 m edge effect belt showed the best photosynthetic capacity, which was responsible for the best growth status of Korean pine in this treatment plot. Leaf water potential, leaf temperature, vapor pressure deficit of leaf were positive correlated with the stomatal conductance. Thus, the high light in the 8 m edge effect belt induced the higher leaf temperature, vapor pressure deficit of leaf and lower water potential may be responsible for the sharp decrease in 8 m edge effect belt. Therefore, based on our present study, too wide (8 m) and too narrow (4 m) width can result in the photosynthetic ecophysiological maladjustment (as discussed above). The optimal candidate width of edge effect belts in afforestration of Korean pine in the secondary oak forest may be 6 m.