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作 者 ：春亮;陈范骏;宋建兰;米国华

期 刊 ：植物营养与肥料学报 2006年 12卷 6期 页码：811-815

关键词：铁浓度；子粒；氮供应；玉米；

Keywords:Fe concentration, kernel, nitrogen supply, maize,

摘 要 ：谷物子粒的铁营养是影响人及动物营养状况的重要因素之一,但对子粒铁营养的生理限制因素了解十分缺乏。氮素供应可能通过影响营养器官中的物质转移从而影响子粒铁的供应。本研究以玉米为材料,在田间两个氮水平(施氮、不施氮)下研究了吐丝至成熟期玉米从土壤中铁的吸收量、不同营养器官中铁的输出量、及其对子粒铁的表观贡献率,探讨了氮素供应对这些过程的影响。结果表明,氮素供应对子粒铁浓度没有显著影响,两个氮水平下,茎(含叶鞘)中铁的净输出量为1.25～1.71.mg/plant、输出率为40.4%～48.2%,对子粒铁的表观贡献率为50.9%～69.8%。中部叶片(穗位叶及其上、下各两片叶)中铁的含量表现为净增加。不施氮时营养器官中铁的净输出量和输出率低于施氮,而吸铁量对子粒铁的表观贡献率却高于施氮。两个氮水平下,吐丝至成熟期子粒铁的“源”(营养器官输出铁与从土壤中吸收的铁之和)的供应能力均大于子粒铁的累积能力(累积量),说明铁的吸收和转运可能不是决定子粒铁浓度的主要因素,子粒中铁的卸载及代谢可能是限制子粒铁营养的主要生理过程。

Abstract:Iron(Fe) nutrition of cereal grains has substantial influence on human and animal health.This trait can be determined by many physiological processes such as Fe uptake,transport in xylem,storage in vegetative organs,retranslocation via phloem to grains and deposition in grains.Much progress has been achieved in understanding of iron uptake.Nevertheless,less is known about the physiological basis for Fe nutrition in grains.Nitrogen(N) has substantial influence on iron nutrition in plants in many aspects.For example iron availability to plants is higher with ammonium compared with nitrate.Regarding to iron accumulation in grains,N supply may affect Fe concentration of grains by changing the export of Fe from vegetative organs.In the present study,after silking Fe uptake and export from different vegetative organs of maize and their potential contribution to kernel Fe accumulation was investigated under high and low N supplies.It was showed that N levels had no significant influence on Fe concentration in kernels.Under both N levels,stem(including sheathes and tassels) had the highest Fe export amount,Fe export percentage(40.4%—48.2%) and the potential contribution percentage(50.9%—69.8%) to kernel Fe.The middle leaves(ear-leaf and the 2 leaves above,the 2 leaves below),on the contrary,showed net increase of Fe content.Compared with high N,Fe export amount and percentage from vegetative organs was lower,while Fe uptake was higher under low N.The total Fe source,including post-silking Fe uptake and Fe export from vegetative organs,was more than the amount of Fe accumulated in kernels under both N levels,which indicated that Fe uptake and transport were not the limiting factors for kernel Fe accumulation.It is suggested that loading and metabolism of Fe in kernels may be the limiting factor for Fe accumulation.

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