摘要
【目的】为了研究不同造林密度对杂交马褂木人工林林分生长和光合因子的影响，为在亚热带地区种植杂交马褂木，确定其营林措施提供科学依据。【方法】研究对象为设置在江苏下蜀林场的杂交马褂木多密度实验林，利用鱼眼相机拍摄全天空照片，采用Hemiview软件反演冠层有效叶面积指数（LAIe）和叶面积密度（LAD），同时结合林地调查数据和和地基激光扫描点云数据分别密度进行胸径（DBH）、冠幅（W）等基本测树因子与LAI的相关性分析，分析生长适应性并寻找适宜种植密度。接着使用光合仪测定光响应曲线及相关参数，分析各密度马褂木的净光合速率、水分利用率和蒸腾速率等因子对光合辐射强度的反应。用直角双曲线模型、非直角双曲线模型、指数函数模型、双曲线修正模型拟合光响应曲线，分别五个种植密度对比模型效果，从而为杂交马褂木选择最优光响应模型，分析生长适应性来研究适宜的种植密度。【结论】（1）5个密度的样地LAIe值均与其胸径有显著相关关系，5x5密度马褂木LAIe与胸径呈显著负相关关系；各密度第一分枝高度与LAIe相关性不显著。（2）当光照条件一定，1x1密度马褂木LAIe与2x2密度、3x3密度、4x4密度马褂木LAIe差异性显著。5x5密度马褂木LAIe和2x2密度、3x3密度、4x4密度马褂木LAIe差异性极显著。（3）2x2密度和4x4密度的马褂木净光合速率明显大于其他密度，2x2密度马褂木水分利用速率明显大于其他密度，2x2和4x4密度马褂木光合能力强，2x2密度马褂木水分利用效率高，能量转化效率高；（4）双曲线修正模型的决定系数（R2）是四个模型中最高的，说明双曲线修正模型拟合效果最佳。2x2密度马褂木的表观量子效率和最大净光合效率均最高，说明2x2种植密度的马褂木更具生长优势。
关键词：多密度、杂交马褂木、冠层结构、叶面积指数、光响应曲线
Analysis of Canopy Leaf Area Index and Photosynthesis of Multi-density Liriodendron hybrids
ABSTRACT
[Objective] This study explored the effects of different afforestation densities on the growth and photosynthetic factors of the Liriodendron hybrids, and provided a scientific basis for determining the forest management measures for the Liriodendron hybrids in the subtropical region.[Method] Variety of densities of Liriodendron hybrids from Xiashu Forest Farm in Zhenjiang were used as the test object,and the effective leaf area index of the canopy was retrieved by Hemiview software using fisheye camera，at the same time, combine the forest land survey data and the density of the ground-based laser scanning point cloud data to analyze the correlation between the basic tree measuring factors such as Diameter at breast height and crown width and LAI, analyze the growth adaptability and find the appropriate planting density. Then use a photosynthetic instrument to measure the light response curve and related parameters, and analyze the net photosynthetic rate, water use efficiency and transpiration rate of each density of the Liriodendron hybrids to the photosynthetic radiation intensity. According to the fitting effect of right angle hyperbola model, non right angle hyperbola model, exponential function model and hyperbola correction model, the optimal model was selected to analyze the growth adaptability and suitable planting density of Liriodendron hybrids.[Result] (1)There was a significant correlation between the LAIe value of 5 densities and the diameter at breast height, and the LAIe of 5x5 density was significantly negatively correlated with the diameter at breast height; the first branch height of each density was not significantly correlated with LAIe.(2) Under the same light condition, the LAIe of Liriodendron hybrids at 1x1 density was markedly different from that of Liriodendron hybrids at 2x2 density, 3x3 density and 4x4 density. Lai of Liriodendron hybrids at the density of 5x5 was significantly different from that of Liriodendron hybrids at the density of 2x2, 3x3 and 4x4. (3)The net photosynthetic rate of Liriodendron hybrids at 2x2 and 4x4 densities was significantly higher than that of other densities, and the water use rate of Liriodendron hybrids at 2x2 and 4x4 densities was significantly higher than that of other densities. Photosynthetic capacity of Liriodendron hybrids for 2x2 and 4x4 densities was strong, and the water use efficiency and energy conversion efficiency of Liriodendron hybrids at 2x2 and 4x4 densities were high.(4)The determination coefficient (R2) of the hyperbolic correction model is the highest among the four models, which indicates that the hyperbolic correction model has the best fitting effect.The apparent quantum efficiency and the maximum net photosynthetic efficiency of Liriodendron hybrids with 2x2 planting density were the highest, indicating that Liriodendron hybrids with 2x2 planting density had more growth advantages.
Key Words: multi-density、Liriodendron hybrids、canopy structure、leaf area index、Light response curve
目 录
1前言 1
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