中文摘要：

以豫麦49-198、漯麦18（低氮高效型,LH）和西农509、矮抗58（低氮低效型,LL）4个品种为材料,采用盆栽试验研究3个不同施氮水平（0、120、225 kg/hm^2N）下小麦不同生育时期的氮素转运特征,并分析谷氨酰胺合成酶（GS）活性、氮代谢指标（游离氨基酸、可溶性蛋白含量）及两者的相关性。结果表明,LH型品种的籽粒氮素分配比例均高于LL型品种,且氮素分配比例随着施氮量的增大而减小;LL型品种的营养器官氮素分配比例较LH型品种高,且氮素分配比例总体随施氮量的增大而增大;总体上功能叶和穗下节中GS活性表现为LH型〉LL型,且随施氮量的增加而增加;总体上不同施氮量处理功能叶和穗下节中游离氨基酸、可溶性蛋白含量均随施氮量的增加而增大,不同氮效率品种的功能叶和穗下节中游离氨基酸、可溶性蛋白含量均表现为LH型〉LL型;功能叶和穗下节中GS活性与可溶性蛋白、游离氨基酸含量的相关性均达到显著或极显著水平,且在开花后7 d时相关性达到最高。花后7 d时的GS活性可作为小麦营养诊断的一个参考指标。

英文摘要：

Yumai 49-198 and Luomai 18 with high nitrogen use efficiency（ NUE） under low nitrogen level（ LH type）,Xinong 509 and Aikang 58 with low NUE under low nitrogen level（ LL type） were chosen as materials to study the nitrogen metabolism characteristics of wheat varieties with different NUE and the correlation between GS activity and nitrogen metabolism markers（ free amino acid content,soluble protein content） under nitrogen levels of N0（ 0 kg / ha）,N120（ 120 kg / ha） and N225（ 225 kg / ha） in the field by pot experiment. The results showed that grain nitrogen distribution proportion of LH type washigher than that of LL type,and decreased with the increase of fertilizer supply; vegetative organs nitrogen distribution proportion of LL type was higher than that of LH type,and increased with the increase of fertilizer supply; on the whole,GS activity of function leaf and peduncle of LH type was significantly higher than that of LL type,and increased with the increase of fertilizer supply; on the whole,the free amino acid and soluble protein contents showed LH type〉 LL type in function leaf and peduncle,and increased with the increase of fertilizer supply; there were significant relationships between GS activity and free amino acid,soluble protein contents in function leaf and peduncle,the correlation coefficient reached the highest value at 7 d after anthesis. GS activity could be a reference index to diagnose the nutritional status of wheat at 7 d after anthesis.