不同氮效率玉米杂交种的营养生长及光合特征

以氮效率不同的4个玉米杂交种(组合)为材料,在两个氮水平下分析了营养生长及光合特征。结果表明,施氮条件下玉米营养体的含氮量平均在2.0%左右,低氮处理下降到1.5%左右;氮高效品种的穗位叶光合效率并没有降低,氮低效品种的叶片光合效率则显著降低。氮高效品种在叶片保绿性方面明显具有优势,在低氮条件下保持了较大的绿叶面积和较高的叶绿素含量。这些特征保证了氮高效品种后期光合产物供应能力强,并用于子粒灌浆。

Vegetative Growth and Photosynthetic Characteristics of Maize Hybrids Differing in Nitrogen Use Efficiency

In this study, 4 maize hybrids with different N use efficiency (grain yield / N supply) were used to analyze the contribution of vegetative growth and photosynthetic characteristics to N efficiency. It was found that low N reduced N concentration of stem and leaves sharply from 2% to 1.5% on average in whole growth period. The net photosynthetic rate(Pn) of the ear-leaf of the N-efficient cultivars (NE1 and ND108), however, did not decrease, while that of the N-inefficient cultivars (209×115, SD19) decreased significantly. N-efficient cultivars had the advantage to stay green at grain filling stage. They showed larger green leaf area and chlorophyll content (SPAD value) at low N stress. It was supposed that the advantageous photosynthetic characters of the N-efficient cultivars contribute to more photosgnthetic supply for grain filling.