甜玉米氮素积累和分配的基因型差异

为了解甜玉米高产品种氮素积累和分配的规律，阐明不同生育阶段氮素积累和分配的基因型差异，及其对产量形成及氮素利用效率的作用，分析了22个甜玉米品种在同一施氮水平下拔节期、开花期和鲜食期的植株氮素积累量和分配量。结果表明，甜玉米品种不同阶段的氮素积累和分配存在着显著的基因型差异。随着生育进程的推进，植株氮素含量逐渐下降，氮素积累量逐渐上升，不同生育阶段的氮素积累量以拔节到开花期最高；氮素在开花前主要分布在叶片中，在开花后开始由叶片逐渐向果穗转移。到鲜食期，甜玉米不同品种果穗中氮素分配量最高，占全株氮素总积累量的41.32%，其次为子粒，氮素分配量占全株氮素积累量的28.53%。高产品种拔节—鲜食期氮素积累量高，鲜果穗高产品种在鲜食期叶片和子粒中的氮素分配较高，鲜子粒高产品种在鲜食期叶片和雄穗中氮素分配量较高且轴中氮素分配量较低。鲜果穗氮素利用效率高的品种主要是由于其减少了开花—鲜食期的氮素积累量，其次是减少了拔节—开花期的氮素积累量，且其在鲜食期叶片、轴和叶鞘中的氮素分配量较少。鲜子粒氮素利用效率和各阶段的氮素积累量及鲜食期各器官的氮素分配量无显著相关关系。

Genotypic differences in nitrogen accumulation and distribution among different sweet maize varieties

In order to understand nitrogen (N) accumulation and distribution in sweet maize variety with high fresh ear and kernel yield, explain the genotypic differences of N accumulation and distribution at different growth-phases and their effects on yield formation and N utilization efficiency (NUE), 22 sweet maize (Zea mays L. saccharata Sturt) varieties released in recent years in China were planted and their N accumulation and distribution amount at jointing stage, silking stage and fresh stage under the same nitrogen level were studied. The results indicated that the N accumulation and distribution were significantly different among sweet maize varieties. With the advance of growth and development, plant N content gradually decreased, N accumulation amount gradually increased and the N accumulation amount was highest from jointing to silking stage among different stages. N was mainly distributed in leaf before silking stage and was translocated to ear in grain filling stage. At fresh stage, N distribution amount was highest in ear among various organs, and it accounted for 41.32% of the total N accumulation amount, second was grain, which accounted for 28.53% of the total N accumulation amount. The variety with high yield had high N accumulation amount from jointing stage to fresh consumption stage. The variety with high fresh ear yield had high N distribution amount in leaf and grain at fresh stage, the variety with high fresh grain yield had high N distribution amount in leaf and tassel and low N distribution amount in cob at fresh stage. The variety with high N use efficiency for fresh ear yield mainly reduced N accumulation amount from silking stage to fresh stage, and secondly reduced N accumulation amount from jointing stage to silking stage, and the N distribution amount in leaf, cob and sheath was low. No significant correlations were observed between fresh grain N use efficiency and N accumulation amount at various stages and N distribution amount in organs at fresh stage.