摘要
在模拟遮荫条件下对扁穗牛鞭草的净光合速率、生长指标和经济效益进行了分析。结果表明，扁穗牛鞭草在自然光强1200μmol／（m^2·s）左右时达到饱和点，遮荫48％～79％的光强下很难达到光饱和状态；在中、低光强辐射时，遮荫16％～79％的净光合速率仅为全光下的33．8％～86．4％，高光强辐射下，不同遮荫度下的净光合速率为其全光照的35．0％～94．7％；不同光照强度或者同一光照强度的不同遮荫梯度下，扁穗牛鞭草净光合速率都表现出显著差异[F遮荫=44．09：〉F0.05（3．84），Pv〈0．05；F光照=11．72〉F0．05（4．46）．Pv〈0．05]；遮荫改变了光照条件，影响光合产物的合成，进而抑制了扁穗牛鞭草的茎粗生长、植株萌发以及生物量的积累，对株高生长则表现为抑制和促进2个方面；不同遮荫梯度下扁穗牛鞭草产值下降幅度为35．0％～83．1％，年产出0．5123万元／hm^2为扁穗牛鞭草种植的临界值，林（竹）-扁穗牛鞭草模式的冠层遮荫度需等于或小于43％，才能有一定的经济效益。
Different shading environments were simulated to analyze their influence on the net photosynthetic rate （Pn） and growth of H. cornpressa and their respective economic results. The Pn saturation point is at 1 200μmol/（m^2·s） and is difficult to reach it when shading degree is between 48%-79%. Comparing Pn under 16%-79% shading environment to that of no shade, the rate is 35.0%-94.7% with high light luminosity, while the same comparison gets a rate of 33.8%-86.4% with lower light luminosity. The Pn shows obvious differences under the same shading degree but different light luminosity or the same light luminosity but different shading degrees（Fshade=44.09〉F0.05 （3.84） ,Pv0.05;Flight=11. 72〉F0.05 （4.46）, Pv〈0.05）. Shading reduces the illumination, slows photosynthetic production and restricts the stem width, the number of sprouts and the hiomass of H. compressa, but its influences on the plants height can be either way. The total output of H. compressa can decline 35.0 %-83.1% under 16%-79% shading environment. Assuming annual revenue of 5. 123 thousand yuan per hm^2 as the basic requirement for planting H. compressa with economic benefits, the trees-grasses shading needs to be less than or equal to 43%.
出处
《草业学报》
CSCD
2006年第2期54-59,共6页
Acta Prataculturae Sinica
基金
国家科技部"十五"重点攻关项目(2001BA606A-06)
四川省教育厅重点学科建设项目(2003)资助
关键词
遮荫
净光合速率
生长
经济效益
shading
net photosynthetic rate
growth
economic benefits
