作　　者： ; ; ;

机构地区： 北京林业大学林学院森林培育与保护教育部重点实验室

出　　处： 《生态学报》 2011年第17期4889-4899,共11页

摘　　要： 采用涡度相关法对华北平原夏玉米田进行了连续4a(2003—2006年)的碳通量观测,结果表明:夏玉米田生态系统初始量子效率(α)、最大光合速率(Pmax)、暗呼吸速率(Rd)和总初级生产力(GPP)随作物生长发育而变化。在夏玉米生育前期和后期,α、Pmax、Rd和GPP都比较小,其最大值出现在抽穗期/灌浆期。2003—2006年,夏玉米生长季平均α、Pmax、Rd的范围分别为0.054—0.124μmol/μmol、1.72—2.93 mg CO.2m-.2s-1、0.23—0.38 mg CO.2m-.2s-1。α、Pmax和Rd均随叶面积指数(LAI)增加呈指数增长。2003—2006年夏玉米生长季GPP总量分别为806.2、741.5、703.0、817.4 g C/m2,年际差异较大。玉米田生态系统GPP随温度升高呈指数增长。在玉米营养生长阶段,GPP随LAI增加而增大,两者之间的关系可用直角双曲线方程来表示;生殖生长阶段,GPP随LAI降低而下降。相同LAI下,生殖生长阶段的GPP明显低于营养生长阶段。 Light-response parameters of plant photosynthesis are important indices characterizing ecosystem productivity.Gross primary production（GPP） is one of the most basic energetic and biogeochemical characteristics of an ecosystem.The study of plant photosynthesis at the canopy and ecosystem scales is improved by using micrometeorological methods such as the eddy covariance technique.To investigate photosynthesis and its light-response characteristics,CO2 flux was continuously measured using the eddy covariance technique in a summer maize field on the North China Plain from 2003 to 2006.Net ecosystem carbon exchange（NEE） rose with increase in photosynthetically active radiation and their relationship was expressed by a rectangular hyperbola function.Light-response parameters and GPP showed temporal variation and generally peaked at the heading/grain filling stage.The seasonal mean initial light use efficiency（α）,maximum photosynthesis rate（Pmax） and dark ecosystem respiration（Rd） in the summer maize field varied from 0.054 to 0.124 μmol/μmol,from 1.72 to 2.93 mg CO2·m-2·s-1,from 0.23 to 0.38 mg CO2·m-2·s-1,respectively.Light-response parameters were significantly affected by maize growth.Monthly mean α,Pmax and Rd rose exponentially with the increase in leaf area index（LAI）.About 50% of the changes in α,Pmax and Rd can be ascribed to the variation in LAI.Usually,weak light reaching the ground is mainly composed of scattered light.Under a large LAI,a suitable canopy structure was advantageous for absorbance of scattered light from all directions and led to a high use efficiency of weak light.In summer,the temperature was high and varied within a narrow range.The influence of temperature on Rd was insignificant.LAI was the main factor controlling Rd.Total seasonal GPP in the maize field was 806.2,741.5,703.0 and 817.4 g C/m2 in 2003,2004,2005 and 2006,respectively.The interannual differences in GPP were largely attributable to climatic variation.Compared with the other years,the low GPP

关 键 词： 夏玉米田 光合参数 总初级生产力 涡度相关 叶面积指数 气温

领　　域： [农业科学]