桐麦间作系统小麦群体光合量及其与产量的关系

桐麦间作系统内外小麦的对比研究表明，开花期和灌浆期系统内外各点小麦旗叶的最大光合速率差异不明显；成熟期小麦旗叶的最大光合速率明显下降，并且系统内低于系统外，西冠下低于东冠下．系统内外各点小麦群体光合速率的日变化与其接收的光合有效辐射量的变化规律基本上是一致的．开花期系统内外各点小麦群体总光合差异不明显，灌浆期和成熟期差异较明显，其中灌浆期系统内各点仅为对照的４０％～６６％，且冠外点明显高于冠下各点，西冠下点又稍高于东冠下点；成熟期总光合量较小，系统内各点仅为对照的２０％～５５％．系统内外各点小麦产量与开花期至成熟期群体光合量关系十分密切．各点干物质产量与作物产量比值（ξ）在０．５２～０．７７之间，其中，对照区与系统内冠外点ξ值比系统内冠下各点要低，而东冠下各点稍大于西冠下各点，ξ值的变化与种子数量呈反比．千粒重与灌浆期总光合量紧密相关．

Canopy Photosynthesis of Wheat Crops and Its Relationship with Yield in the Inter Cropping System of Paulownia Wheat

Based on a comparative study of wheat crops inside and outside the inter cropping system of Paulownia wheat, the maximum photosynthetic rates of the flag leaves of wheat were found not significantly different during flowering and grain filling stages, but decreased significantly during maturing stage;the maximum photosynthetic rate of the flag leaves inside the system were significantly lower than that outside the system. The maximum photosynthetic rate of flag leaves of the wheat crops below the crowns of the western tree belt was lower than that of the eastern tree belt. The diurnal variation of canopy photosynthesis of the wheat crops was similar to the variation of incoming photosynthetically active radiation at different locations inside and outside the system. Total amount of canopy photosynthesis of the wheat crops at different locations inside and outside the system was not significantly different during flowering, but significantly different from grain filling to maturing.Canopy photosynthesis of wheat crops inside the system was only 40% to 66% and 20% to 55% of that of the wheat crops outside the system during grain filling and maturing, respectively. Yield of wheat crops at different locations inside and outside the system was closely related to the total amount of canopy photosynthesis of the crops from flowering to maturing. Grain weight is closely related to the amount of canopy photosynthesis during grain filling. These findings provide a theoretical basis for evaluating and optimizing the inter cropping system of Paulownia wheat.