摘要
通过对扁穗牛鞭草地不同层面光合作用差异及贡献率的研究，结果说明：外界光舍有效辐射从上往下以19、84μmol／（m^2·s·cm）速度递减；Ci起伏较大，最大值c（CO2）=943．11μmol／mol出现在最下层光合速率最低的8cm处，最小值c（CO2）=147．81μmol／mol出现在光合速率最高的65cm处；Cs的变化范围为0．033～0．220mol／（m^2·s），但从下往上递增，在顶层有所下降；Tr与Cs密切相关：不同层面叶片单位面积的既差异很大，8cm处c（cO2）=2．42μmol／（m^2·s），65cm处c（CO2）=42．57μmol／（m^2·s）达最大值。单叶光合效率变异范围为1、105～53、450nmol／s，单叶光合效率是外界光合作用有效辐射与叶片面积和光舍速率三者共同偶合作用的结果；不同株层贡献率差异很大，0—20cm光合贡献率仪1．73％，0～40ml的贡献率仅为12．19％，而55—75cm占全部叶片数的40．89％，光舍贡献率达56．88％：扁穗牛鞭草地应当在低于80cm时利用，不仅可以保证牧草的产量与质量，也可以提高草地的年生产能力。
The photosynthetic parameters including the photosynthesis available radiation（PARo）, the guide stoma（ Gs ）, the concentration of intercellular CO2（Ci）, the transpiration rate（Tr）, the photosynthesis rate（Pn） of different leaf layers（8, 12, 15, 20, 25,35, dO, 45, 50, 55, 65, 75 and 80） for artificial grassland of Hemarthria compressa were measured, which was in vegetative growth phase with the density of do plant/m^2, nature height of 80cm, CO2 density of （372±8） μmol/mol, temperature of （33±1） ℃ and relative humidity of （45±3）%. The leaf distribution and its photosynthetic characteristic in different layers, the photosynthetic characteristic and the contribution rate of different height were analysed and studied, The results showed that, from upper to low, the photosynthesis available radiation was gradually decreasing with the velocity of 19,84μmol/m^2.s.cm. The larger wave was found in the Ci parameter, and the largest value [ CO2 943.11 μmol/（m^2.s.cm） ] was emerged in the leaf layer of 8 cm, which had the lowest photosynthesis rate, and the smallest value[CO2 147.81 μmol/（m^2.s.cm）] was the leaf layer of 65 cm, with the highest photosynthesis rate. Gs had the change range of H2O 0,033 - 0.220 mol/（m^2.s.cm）, which was gradually increasing from low to upper, hot at the top layer the value slightly dropped. Tr was obviously relative to G6. There was a visible difference among the Pn value of unit area in different leaf layers, with the smallest value of CO2 2.42 μmol/ （m^2.s.cm） in 8 cm height and the largest value of CO2 42.57 μmol/（m^2.s. cm） in 65 cm height. The simple leaf＇ s photosynthetic efficiency was the resuit of collaborative action of available radiation, leaf area and photosynthesis rate, and its fluctuant range was CO2（11.05 - 534.50） × 10^-4μmol/（m^2. s.cm）. The different heights of plant had different photosynthesis contribution rotes, the rate of 0-20 cm and 0 - 40 cm was 1.73% and 12.19%, respectively, while the ra
出处
《安徽农业科学》
CAS
北大核心
2006年第11期2386-2388,2509,共4页
Journal of Anhui Agricultural Sciences
基金
四川省青年基金项目(02ZQ026-057)
科技部星火计划项目(2004EA810010)资助
关键词
扁穗牛鞭草
人工草地
光合作用
光合作用速率
草地管理
Hemarthria compressa
Artificial grassland
Photosynthesis
Photosynthesis rate
Grassland management
