高产玉米‘郑单958’和‘先玉335’的灌浆和叶片光合特性的比较

Comparion of Grain Filling and Leaf Photosynthetic Characteristics in HighYield Maize ‘Zhengdan 958' and ‘Xianyu 335'

本实验以玉米高产品种‘郑单958’和‘先玉335’为材料,测定在45 000株·hm-2(低密度)和75 000株·hm-2(高密度)下灌浆期的百粒重、叶面积指数、比叶重、叶绿素和类胡萝卜素含量、光合速率、叶绿素荧光参数Fv/Fm的变化。结果表明,在低密度下,‘郑单958’灌浆期的叶面积指数大于‘先玉335’,但百粒重、比叶重、叶绿素含量和光合速率低于‘先玉335’;在高密度下‘郑单958’灌浆期的叶面积指数、百粒重、比叶重、叶绿素含量和光合速率都低于‘先玉335’;密度增大对‘郑单958’灌浆和光合能力的影响大于‘先玉335’;灌浆前期的物质积累速率对籽粒的增重更为重要,其与同期的叶面积指数、比叶重和光合速率相关;在灌浆期,两个品种的叶绿素荧光参数Fv/Fm没有明显的差异;灌浆期的比叶重与籽粒灌浆能力、叶片光合速率和叶绿素含量有良好的一致性。

In this experiment, high-yield maize hybrids ‘Zhengdan 958＇ and ‘Xianyu 335＇ were planted under 45 000 plants·hm^-2（low density） and 75 000 plants·hm^-2（high density）. During the grain-filling stage, the changes in the weights per 100 kernels, leaf area index, specific leaf weights, chlorophyll and carotenoid contents, photosynthetic rates and chlorophyll fluorescence parameter Fv/Fm were measured. The results showed that, in low density, leaf area index of ‘Zhengdan 958＇ was higher than that of ‘Xianyu 335＇, but the weights per 100 kernels, specific leaf weights, chlorophyll contents and photosynthetic rates of ‘Zhengdan 958＇ were lower than those of ‘Xianyu 335＇ during the grain-filling stage. In high density, leaf area index, the weights per 100 kernels, specific leaf weights, chlorophyll contents and photosynthetic rates of ‘Zhengdan 958＇ were lower than those of ‘Xianyu 335＇. The increase of plant density imposed greater effect on the grain filling and leaf photosynthetic characteristics in ‘Zhengdan 958＇ than in ‘Xianyu 335＇. The accumulation rate of assimilates at the earlier stage of grain filling was more important to the final weight of kernels. The assimilate accumulation rate was related to leaf area index, specific leaf weight and photosynthetic rate. There was no significant difference in chlorophyll fluorescence parameter Fv/Fm of the grain-filling stage between the two hybrids. The specific leaf weight of the grain-filling stage had a good correlation with the grain filling capacity, photosynthetic rate and chlorophyll content.