PLANT COMPETITION FOR LIGHT ANALYZED WITH A MULTISPECIES CANOPY MODEL .3. INFLUENCE OF CANOPY STRUCTURE IN MIXTURES AND MONOCULTURES OF WHEAT AND WILD OAT
PLANT COMPETITION FOR LIGHT ANALYZED WITH A MULTISPECIES CANOPY MODEL .3. INFLUENCE OF CANOPY STRUCTURE IN MIXTURES AND MONOCULTURES OF WHEAT AND WILD OAT
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DOI：
10.1007/bf00319801
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发表时间：
1990-01-01
期刊：
影响因子：
2.7
通讯作者：
CALDWELL, MM
中科院分区：
文献类型：
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作者：
BARNES, PW;BEYSCHLAG, W;CALDWELL, MM
利用多物种冠层光合模拟模型研究了小麦混交林和纯林冠层结构对光合作用的影响。和野燕麦（Avena fatua L.），小麦的一种常见的杂草竞争者。在混合物中，模拟的冠层光合作用小麦贡献的分数被发现在生长季节下降，这种下降是密切相关的减少在冠层上层的叶面积。对于这两个物种的混合物和单作，模拟光合作用是最大的中间或中上层冠层和敏感性分析表明，冠层光合作用是最敏感的叶面积和叶倾角在这些层的变化。叶面积指数和叶倾角的变化影响冠层碳增益的混合和单作，但两种物种的反应是不一样的。模拟结果表明，两个物种的结构特征被取代的叶倾角，叶鞘面积和叶面积的分数的物种差异是轻微的后果相比，在影响相对冠层碳增益的混合物中的总叶面积的差异。在这些物种的混合物中，光的竞争似乎是最受影响的叶面积在上层冠层的定位的差异，在很大程度上，光截获的量。
A multispecies canopy photosynthesis simulation model was used to examine the importance of canopy structure in influencing light interception and carbon gain in mixed and pure stands of wheat (Triticum aestivum L.) and wild oat (Avena fatua L.), a common weedy competitor of wheat. In the mixtures, the fraction of the simulated canopy photosynthesis contributed by wheat was found to decline during the growing season and this decline was closely related to reductions in the amount of leaf area in upper canopy layers. For both species in mixture and in monoculture, simulated photosynthesis was greatest in the middle or upper-middle canopy layers and sensitivity analyses revealed that canopy photosynthesis was most sensitive to changes in leaf area and leaf inclination in these layers. Changes in LAI and leaf inclination affected canopy carbon gain differently for mixtures and monocultures, but the responses were not the same for the two species. Results from simulations where the structural characteristics of the two species were substituted indicated that species differences in leaf inclination, sheath area and the fraction of leaf area alive were of minor consequence compared with the differences in total leaf area in influencing relative canopy carbon gain in mixtures. Competition for light in these species mixtures appears to be influenced most by differences in the positioning of leaf area in upper canopy layers which determines, to a great extent, the amount of light intercepted.