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光合有效辐射(PAR)是影响生态系统能量转化和物质生产的重要生态因子,对其时空格局的研究,有助于深入理解生态系统的生理生态因子变化和光合行为。本研究分析了2009年哀牢山亚热带常绿阔叶林生态系统PAR的时间与垂直分布特征及相互关系。结果表明,在日尺度上,PAR在进入冠层内部的过程中,其强度不断减弱;各层次PAR月总量的年变化不尽相同,冠层上在2月和1月分别达到最大值和最小值。冠层上的PAR(PAR1)的日均变化呈单峰曲线,冠层底部(PAR2)、乔木亚层(PAR3、PAR4)和灌木层(PAR5)则为不规则的单峰曲线;各层全年PAR总量分别为8824.98、682.20、403.09、216.62、208.52mol.m-2。全年PAR2-PAR5占PAR1的比率分别为7.73%、4.57%、2.45%和0.92%;雨季各层次PAR的平均值分别为干季的89.77%、89.34%、97.32%%、116.36%和115.09%。
Photosynthetically Active Radiation (PAR) is an important ecological factor that affects the energy conversion and material production of ecosystems. The study of its temporal and spatial pattern will help to understand the changes of ecophysiological factors and photosynthetic behavior of ecosystems. This study analyzed the temporal and vertical distribution characteristics and correlation of PAR in the subtropical evergreen broad-leaved forest ecosystem in Ailao Mountain in 2009. The results showed that on the daily scale, the intensity of PAR continuously weakened while entering the inner canopy. The annual variation of total PAR amount at each level was not the same, and the maximum reached on the canopy in February and January respectively Minimum The daily average change of PAR (PAR1) on the canopy showed a single peak curve. The PAR2, PAR4 and PAR5 showed an unimodal curve. The total annual PAR were 8824.98,682.20,403.09,216.62,208.52mol.m-2. In the whole year, the PAR2-PAR5 accounted for 7.73%, 4.57%, 2.45% and 0.92% of the PAR1 respectively. The average PAR of all levels in the rainy season were 89.77%, 89.34%, 97.32%, 116.36% and 115.09% .