边缘效应带和保留带内红松幼林水分生态的差异  

DIFFERENCES IN WATER ECOLOGY OF A YOUNG PINUS KORAIENSIS STAND GROWN IN EDGE-EFFECT BELTS AND RESERVED BELTS

作　　者：祖元刚[1] 王文杰[1] 王慧梅[1] 

机构地区：[1]东北林业大学森林植物生态学教育部重点研究实验室,哈尔滨150040

出　　处：《植物生态学报》2002年第5期613-620,共8页Chinese Journal of Plant Ecology

摘　　要：以一个经过 12年边缘效应带处理的 14年生红松 (Pinuskoraiensis) (1998年 )幼林生态系统为研究对象 ,对处于不同宽度的边缘效应带和保留带的红松幼树木质部水势、叶片蒸腾强度、气孔导度、叶片温度、空气相对湿度和光合有效辐射的日变化以及土壤相对含水量进行了分析 ,结合叶片净光合速率探讨了效应带宽度对红松幼林生态系统中红松幼树水分生态及红松生长状况的可能影响模式。结果表明 :1)边缘效应带的开拓降低了效应带内红松幼树木质部水势、空气相对湿度和叶片气孔导度 ,显著提高了叶片蒸腾强度、叶片温度和光合有效辐射。但效应带宽度对结果影响较大 ,其中以 8m效应带的影响程度为最大 ,4m效应带最小 ,而 6m效应带居中 ;2 )边缘效应带的开拓使土壤表层相对含水量低于保留带 ,而深层土壤有相反的趋势 ;3)当红松木质部水势下降过低时 ,水分因子可能成为限制红松生长的决定因素而使其生长速度下降 ,如 8m效应带 ,由于水势的过低直接或间接导致了光合午休现象而影响了红松幼树的碳水化合物的积累 ,降低生长速率。但是 ,4m和 6m效应带开拓所引发的木质部水势降低较 8m效应带小 ,对红松生长的影响不大 ,限制红松生长的决定性因素可能是光合有效辐射。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), was studied to evaluate the impact of width of edge-effect belts on water ecological characteristics and growth status of Korean pine. Four meter, 6 m and 8 m strip-cutting belts were chosen as treatment of edge-effect belts and the 10 m undisturbed neighbor belts acted as reserved (control) belts. Both water ecological parameters (xylem water potential, foliar transpiration rate, stomatal conductance for water, soil water content) and non-water ecological parameters (leaf temperature, photosynthetic active radiation, net photosynthesis rate) were measured in this study. The results showed that: 1) the treatment of edge-effect belts could strongly decrease xylem water potential of Korean pine and air relative humidity. Considerable improvements in leaf transpiration rate, leaf temperature, photosynthetic active radiation and a sharp decrease in stomatal conductance were also observed, especially in the 8 m edge-effect belt; 2) soil water content of the edge-effect belts in superficial layer (0-5 cm) was lower than the counterpart in control belts, which might be due to strong evaporation from the soil surface to the atmosphere near ground. However, significantly higher water content in deep layer (20-25 cm) of the edge-effect belts was observed, which might be related to the high water demand of adult oak trees in the reserved belts. This hypothesis needs further research. Furthermore, our results showed that leaf transpiration rate and air humidity, rather than soil water content, correlated with xylem water potential with a significant Pearson-correlation value, indicating the former might contribute more to the diurnal pattern of xylem water potential. Considering the growth performance, foliar photosynthesis traits and water ecological characteri

关 键 词：边缘效应带 保留带 红松幼林 水分生态 差异 木质部水势 蒸腾速率 气孔导度 土壤相对含水量 

分 类 号：S718.5[农业科学—林学]