热带常绿阔叶林冠层光合作用光响应特征  

Light Response Characteristics of Canopy Photosynthesis of a Tropical Evergreen Broadleaf Forest

作　　者：牛晓栋 庞勇[1,2] 徐海龙 余涛 Niu Xiaodong;Pang Yong;Xu Haiong;Yu Tao(Research Institute of Forest Resources Information Techniques,Chinese Academy of Forestry,Beijing 100091,China;Key Laboratory of Forestry Remote Sensing and Information System,National Forestry and Grassland Administration,Beijing 100091,China;Institute of International Rivers and Eco-Security,Yunnan University,Kunming 650500,China)

机构地区：[1]中国林业科学研究院资源信息研究所,北京100091 [2]国家林业和草原局林业遥感与信息技术重点实验室,北京100091 [3]云南大学国际河流与生态安全研究院,昆明650500

出　　处：《陆地生态系统与保护学报》2024年第2期24-31,共8页Terrestrial Ecosystem and Conservation

基　　金：高分辨率对地观测系统重大专项项目(30-Y30A02-9001-20/22-7)。

摘　　要：【目的】研究云南省典型热带常绿阔叶林的冠层光合作用光响应特征,为理解森林碳汇时空变化特征提供科学依据。【方法】基于云南省景洪市普文热带常绿阔叶林通量塔从2023年3月至2024年2月的观测数据,利用Michaelis-Menten方程,以1个月为时间窗口,拟合生态系统光合作用的3个光响应特征参数(以下简称“光合参数”),并与相应时间尺度的环境因子平均值进行相关分析。【结果】热带常绿阔叶林的表观初始光能利用效率(apparent initial light use efficiency,ɑ)和生态系统暗呼吸速率(dark ecosystem respiration,R_(d))有相似的季节变异特征,均在10月份达到最大值,2月份为最小值;最大光合速率(maximum photosynthesis rate,P_(max))在3至5月较低,其余月份变化不明显。与ɑ、R_(d)和P_(max)的季节变异相关性最大的环境因子分别是风速、空气相对湿度和饱和水汽压差,冠层导度也对Rd和Pmax的季节变异有一定影响。【结论】热带常绿阔叶林的3个冠层光合参数有明显的季节变异特征,风速和水分条件相比光合有效辐射和空气温度对光合参数的季节变异有更大影响。【Objective】The light response characteristics of canopy photosynthesis in a tropical evergreen broadleaf forest in Yunnan Province was studied to provide a scientific basis for understanding the spatial and temporal variation characteristics of forest carbon sinks.【Methods】Based on the flux tower data observed from March 2023 to February 2024 in a tropical evergreen broadleaf forest in Puwen Town,Yunnan Province,the Michaelis-Menten equation was used to fit the three photosynthetic parameters of the ecosystems with the time windows of 1 month.And the correlation analysis between ecosystem photosynthetic parameters and environmental factors in corresponding time scale was carried out.【Results】The apparent initial light use efficiency(ɑ)and dark ecosystem respiration(R_(d))showed similar seasonal variation characteristics,with the maximum value in October and the minimum value in February.The maximum photosynthesis rate(P_(max))from March to May was low and had no obvious change in other months.The environmental factors that are most correlated with the seasonal variations ofɑ,Rd and P_(max) were wind speed,relative air humidity and vapor pressure deficit,respectively.Canopy conductance also had an apparent effect on the seasonal variation of R_(d) and P_(max).【Conclusion】Three photosynthetic parameters of the tropical evergreen broadleaf forest showed obvious seasonal variations.Rather than photosynthetically active radiation and air temperature,wind speed and water conditions had greater effects on the seasonal variations of photosynthetic parameters.

关 键 词：天然林 光合参数 涡度相关 饱和水汽压差 云南 

分 类 号：S718.55[农业科学—林学]