阔叶林下人工更新红松幼树光合作用研究

Studies on photosynthetic characteristics for young trees of Pinus koraiensis regenerated artificially in broadleaved forests

利用LI-6400便携式光合测定系统,对天然次生林下、林缘、林窗环境中红松幼树的净光合速率进行测定,同时记录光合生理因子和环境因子。分析了林下、林缘、林窗不同条件下红松幼树的净光合速率、蒸腾速率、光能利用率、水分利用率日进程及其差异。结果表明:日平均气温林下<林缘<林窗;空气相对湿度林下>林缘>林窗;林窗阳面叶光合有效辐射呈单峰型曲线,阳面叶光合有效辐射最大值林窗>林缘>林下;红松幼树净光合速率阳面叶大于阴面叶,林窗处阳面叶净光合速率日变化呈单峰型曲线,林缘呈双峰型曲线,林下呈多峰型曲线,净光合速率最大值林窗>林缘>林下;红松阳面叶的光能利用率林下>林缘>林窗;红松阳面叶蒸腾速率日变化呈单峰型曲线,且蒸腾速率林窗﹥林缘﹥林下,阳面叶﹥阴面叶;红松阳面叶水分利用率林下﹥林窗﹥林缘,阳面叶水分利用率﹥阴面叶水分利用率。

Net photosynthesis rates （NPR） for young plants ofPinus koraiensis in natural secondary forests in such surroundings as in the forests, at the edge and canopy gaps of forests were determined by means of LI-6400 portable photosynthesis system, and physiological and environmental factors were recorded, the diurnal process and differences regarding NPR, transpiration rates （TR）, light utility efficiency （LUE） and water utility efficiency （WUE） of young plants of P/nus koraiensis in above-mentioned conditions were analyzed. The results indicated that： daily average temperature was in the forest〈at the edge〈at canopy gaps, and air relative humidity was in the fores〉at the edge〉at canopy gaps. The photosynthesis active radiation （PAR） of sunshine-side leaves at canopy gaps showed a single peak curve, and maximum PAR was at canopy gaps〉at the edge〉in the forest. NPR for sunshine-side leaf of young plants of Pinus koraiensis was greater than that of shade-side leaf, and NPR diurnal variation of NPR for sunshine-side leaf at canopy gaps, at the edges and in the forest showed a single peak curve, a double-peak curve and a multi-peak curve respectively, the maximum NPR was at canopy gaps〉at the edge〉in the forest. LUE for sunshine-side leafofPinus koraiensis was in the forest〉at the edge〉 at canopy gaps. TR diurnal variation for sunshine-side leaf of Pinus koraiensis showed a single peak curve, and TR was at canopy gaps〉at the edge〉in the forest and sunshine-side leaf〉shade-side leaf WUE for sunshine-side leaf ofPinus koraiensis was in the forest〉at canopy gaps〉at the edge and sunshine-side leaf〉shade-side leaf.