关键词: 小麦, 苗期, 氮素响应

Abstract: To better understand the response mechanism of wheat seedlings under different nitrogen levels,a panel of 12 different wheat genotypes was set to grow under contrast nitrogen input levels by using the Hoagland nutrition solutions with sand.The seedling biomass,root morphology,chlorophyll content of the leaves,the leaves GS enzyme activity as well as the transcripts of the central genes involved in nitrogen uptake and assimilation process were investigated.The results indicated that the seedlings biomass of all the wheat genotypes was significantly increased upon the increase of the nitrogen input.The seedling root/shoot ratio under the low nitrogen level was higher than that under the high nitrogen levels.Although significant difference was observed for the main root growth between the different genotypes under the nitrogen-deficiency conditions,it was found that the nitrogen deficiency stimulated the main root growth and expanded the total root length and total root surface of the wheat seedlings on the whole.Meanwhile,the chlorophyll con-tent of the individual wheat lines were elevated upon the increase of the nitrogen input.However,the GS enzyme activity demonstrated genotypic variations under contrasting nitrogen levels.The gene expression of TaNRT2.1 and TaNRT1.1 exhibited higher transcript un-der low nitrogen conditions.Furthermore,the transcripts of TaNRT2.1 and TaNRT1.1 were higher in the high nitrogen use efficiency wheat lines of Zhengmai 9023 and“410187”than the low nitrogen use efficiency wheat line of Nanong 08Y611.In spite of up-regula-tion of TaGS2 was observed under high nitrogen levels,no significant differences were detected for the expression of TaGS1 with re-spect to the genotype or the nitrogen levels.

Key words: wheat, seedling stage, nitrogen response