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研究结果表明:高产夏玉米群体光合速率日变化呈单峰曲线。在水肥充足栽培条件下,光照强度是影响玉米群体光合速率的主导因素,最大自然光强下群体光合未测到光饱和点。群体光合速率随CO_2浓度(50-900ppm范围)的增加而提高。土壤呼吸释放的CO_2量占群体光合速率的11.68％。高产群体所形成的独特环境对单叶光合速率影响很大,群体生长下的单株,在8×10~4-9×10~4Lx光下的单叶光合速率为果穗叶高于下部和上部叶,品种、密度间差异不大;冠层自然状态下的单位叶面积光合速率上部叶却高于中、下部叶,高密度下,紧凑型品种高于平展型品种,低密度下则相反。
The results showed that the diurnal variation of photosynthetic rate of high-yielding summer maize showed a single peak curve. Under adequate water and fertilizer conditions, light intensity was the dominant factor affecting the photosynthetic rate of maize population, and the maximum photosynthetic rate was not detected at the maximum photosynthetic rate under the maximum light intensity. Population photosynthetic rate increases with CO 2 concentration (50-900 ppm range). The amount of CO 2 released from soil respiration accounted for 11.68% of the photosynthetic rate of the population. The unique environment formed by the high-yielding population had a great influence on the photosynthetic rate of single leaf. The single leaf photosynthetic rate under 8 × 10 ~ 4-9 × 10 ~ 4Lx light was higher than that of the lower and upper leaves Under the natural condition of canopy, the photosynthetic rate of the upper leaves was higher than that of the middle and lower leaves. Under the high density, the compact varieties were higher than the flat varieties and the opposite was the low density.