摘要
【目的】揭示氮高效利用基因型大麦生育后期氮素分配转运的生理机制,为大麦高效氮肥管理和高产栽培提供理论依据。【方法】采用土培盆栽试验,利用前期筛选出的氮高效利用基因型大麦(DH61、DH121+)和低效利用基因型大麦(DH80)为试验材料,分析其在不施氮、低氮(125 mg N·kg-1土)、正常氮(250 mg N·kg-1土)和高氮(375 mg N·kg-1土)4个氮素处理下籽粒产量、生物量及生育后期地上部营养体氮素转移特性和植株氮形态组分构成特征。【结果】(1)随施氮量的减少,不同氮效率基因型大麦籽粒产量和地上部生物量均减少。同一施氮处理,高效基因型大麦籽粒产量和地上部生物量高于低效基因型。不施氮处理下,高效型大麦DH61和DH121+籽粒产量分别是低效型DH80的1.96、2.03倍;低氮处理下分别是低效型DH80的2.10、2.37倍。扬花期和灌浆期,不施氮和低氮处理下两类基因型大麦植株氮浓度无明显差异,氮高效基因型大麦干物质形成能力较强。(2)高效基因型大麦植株能够积累较多的氮素,扬花前高效基因型氮素积累量占大麦生育期氮积累量的比例高于低效基因型。低氮(125 mg N·kg-1土)、正常氮(250 mg N·kg-1土)、高氮处理(375 mg N·kg-1土)下,高效基因花前氮素积累量是低效基因型的1.31、1.38、1.49倍,充足的氮素积累为后期灌浆结实奠定了物质基础。(3)随着氮素用量的增加,氮素转运量呈单峰曲线变化,氮素转移率和氮素转运量对籽粒的贡献率则逐渐下降,过高的氮肥施用不利于氮素向籽粒的转运。高效基因型DH61和DH121+籽粒氮素来源更多依赖于前期地上部营养体的氮素转移,不施氮和低氮氮素转运量对籽粒的贡献率分别为35.06%、40.06%和76.37%、81.72%。而低效基因型DH80籽粒的氮素来源则以后期根系氮素的吸收和转移为主,氮素吸收量对籽粒的贡献率为68.20%和34.84%。(4)相同氮素处理下,扬花至灌浆期大麦茎秆和叶片中营养性氮含量增加,功能性氮含量变化平稳,而结构性氮含量则降低;籽粒营养性氮含量逐渐增加,结构性氮含量缓慢下降。且较低效基因型,高效基因型大麦茎秆和叶片结构性氮含量的降低幅度大,氮素转运能力强。低氮处理下,高效基因型扬花期至灌浆期茎秆和叶片结构性氮含量分别降低49.57%、62.58%;灌浆至成熟期分别降低64.47%、28.11%。【结论】氮高效利用基因型大麦籽粒氮含量受花后茎秆和叶片中结构性氮的分解转化决定,营养器官中结构性氮的再利用有利于氮素利用效率的提高。
Objective]Nitrogen plays important roles in promoting plant growth and development. The objective of this study is to clarify the characteristics of distribution and transportation for barley nitrogen efficiency genotype, and to provide a theoretical basis for efficient nitrogen management and high-yield cultivation of good varieties.【Method】In this study, a soil culture pot experiment was conducted with barley genotype of high nitrogen utilization efficiency （DH61, DH121＋） and low nitrogen utilization efficiency （DH80）. Four nitrogen treatments were designed, including no nitrogen, low nitrogen （125 mgN·kg-1 soil）, normal nitrogen （250 mgN·kg-1 soil） and high nitrogen （375 mgN·kg-1 soil）, respectively. The purpose was analysis grain yield, aboveground biomass , the characteristics of nitrogen transportation and fractions in different organs of barley with high nitrogen utilization efficiency （NUE） at late growth stage.【Result】When applied nitrogen reduced, the amount of aboveground biomass and grain yield were decreased among all tested cultivars. Under the same nitrogen application level, the amounts of biomass and grain yield of high NUE genotype were higher than that of low NUE genotype. The grain yield of high NUE genotype was, respectively, 1.96 times and 2.03 times, 2.10 times and 2.37 times higher than that of low NUE genotype in no nitrogen and low nitrogen treatments. Nitrogen concentration of high and low NUE genotype had no significant difference in no nitrogen and low nitrogen treatments at flowering and grain filling stages. High NUE genotype had a strong ability in dry matter forming. The amount of nitrogen accumulation of high NUE genotype was higher than that of low NUE genotype. And the ratio of nitrogen accumulation during the whole growth period of high NUE genotype was higher than that of low NUE genotype before flowering stage.Nitrogen accumulation of high NUE genotype was 1.48 times, 1.36 times and 1.37 times higher than that of low NUE in low nitrogen （125 mgN·kg-1 soil）, normal nitrogen （250 mgN·kg-1 soil）, and high nitrogen （375 mgN·kg-1 soil） treatments. Adequate nitrogen accumulation of high NUE before flowering had laid a foundation for early filling of seeds. When applied nitrogen reduced, nitrogen translocation showed a single peak curve, nitrogen transfer rate and the amount of nitrogen transported to grain contribution rate gradually declined, over fertilization of nitrogen fertilizer is not conducive to grain transport. For high NUE genotype（DH61,DH121＋）, nitrogen in grain mainly relied on nitrogen translocation from vegetative organs, which accounted for 35.06%, 40.06% and 76.37%, 81.72% in no nitrogen and low nitrogen treatments, respectively but for low NUE genotype（DH80）, nitrogen in grain mainly relied on nitrogen uptake by root at reproductive stage which accounted for 68.20% and 34.84%. Higher transfer efficiency associated with different forms of nitrogen in plant composition and change. In different nitrogen treatments, assimilable nitrogen content in stalk and leaf increased, functional nitrogen content changes smoothly and structural nitrogen content was reduced from flowering to filling, while assimilable nitrogen content increased, and structural nitrogen content slowly declined in grain. High NUE showed a strong decline and nitrogen transport capacity of the structural nitrogen content. The structural nitrogen content of high NUE in stem and leaf decreased by 49.65% and 62.54% in low nitrogen treatment from flowering to filling, and it decreased by 66.54% and 28.17% from heading to maturity.【Conclusion】Grain nitrogen content of high NUE in stems and leaves is decided by the structural nitrogen content decomposition and transformation after flowering, and structural nitrogen recycling in vegetative organsis conducive to nitrogen use efficiency.
出处
《中国农业科学》
CAS
CSCD
北大核心
2015年第6期1151-1161,共11页
Scientia Agricultura Sinica
基金
国家自然科学基金(40901138)
国家科技支撑计划子课题(2008BAD98B03)
四川省科技厅应用基础项目(2010JY0083)
关键词
大麦
氮高效利用基因型
氮素转运
氮组分
barley
high nitrogen utilization efficiency genotype
nitrogen transportation
fractions
