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植物光能利用率(Light Use Efficiency,LUE)作为表征植被利用光能合成生物化学能效率的重要指标,直接影响到生态系统生产力。本文使用2006年4月-10月湖南岳阳站通量观测资料,探讨杨树人工林不同时间尺度的光能利用率动态特征。结果表明:①杨树人工林生态系统典型晴天LUE_(30min)存在明显的“V”形日变化,其值介于(13.18~45.28)mmol/mol,最低值都出现在中午前后;②5日累计光能利用率(LUE_5)季节动态呈双峰型变化,峰值分别出现在5月初(42.57mmol/mol)和7月中旬(57.50mmol/mol);③月尺度光能利用率(LUEmon)分别为24.79、27.85、20.95、42.27、32.60、24.91和10.47mmol/mol,最大值出现在7月份,且LUE_(mon)最大值较LUE5和LUE_(30min)低,最小值较LUE5和LUE_(30min)高。这些结果将为提高生态系统资源的利用提供重要的定量化依据。
Light Use Efficiency (LUE), as an important index to characterize the biochemical energy efficiency of vegetation using light energy, has a direct impact on ecosystem productivity. In this paper, the flux observation data of Yueyang Station in Hunan Province from April to October in 2006 were used to investigate the dynamic characteristics of light energy utilization rate of poplar plantations at different timescales. The results showed that: ① Poplar plantation ecosystem had a clear “V” diurnal variation at a typical sunny day of LUE_ (30 min), ranging from (13.18 to 45.28) mmol / mol, with the lowest value occurring around noon; The seasonal dynamic of daily cumulative solar energy utilization (LUE_5) showed a bimodal pattern with peak values of 42.57 mmol / mol in early May and 57.50 mmol / mol in mid-July, respectively; ③ monthly energy use efficiency (LUEmon) 24.79, 27.85, 20.95, 42.27, 32.60, 24.91 and 10.47 mmol / mol, respectively. The maximum appeared in July and the maximum of LUE_ (mon) was lower than LUE5 and LUE_ (30min) )high. These results will provide an important quantitative basis for improving the utilization of ecosystem resources.