【摘要】 应用¹⁵N 示踪技术,利用克拉克结瘤(R_jl)和不结瘤(r_jl)等位基因系以及3种氮处理造成4种不同氮素营养条件,研究在几种氮源单独或混合供应的情况下,各种来源氮素在大豆生长和产量形成过程中的相对重要性及其相互影响。试验结果表明,大豆前期主要利用土壤和肥料中氮素,并以土壤氮素为主,后期主要利用共生固氮。施氮对固氮有明显抑制作用,其轻、重和时间长短与施肥量有关。施氮可增加大豆对土壤氮的吸收,激发率为1.369～1.778,差异极显著。对营养器官氮素转运率测定结果表明,籽粒中氮素的50%是由营养器官转运而来。在营养器官转运到籽粒的氮素中约50%是来自叶片。测定3种氮源在体内各器官中的分配的结果表明,各种氮源间的分配模式有差异,与总氮的分配模式相比,肥料氮和土壤氮较多地分配于营养器官,空气氮较多地分配于籽粒。更多还原

【Abstract】 The relative importance of different nitrogen sources which wereprovided singly or mixedly to the growth and output formation of soybeanand their interactions were studied by means of¹⁵N tracing techniqueand using nodulating and non-nodulating Clak isolines.Because of the difference between soybean absorption periods,theeffects of various nitrogen sources differed greatly.During the formergrowing period the soybean mainly used the nitrogen from soil and fer-tilizers,of which the soil nitrogen was more important,while during thelatter period,it mainly used symbiotic fixed nitrogen.The applicationof nitrogen fertilizers suppressed the nitrogen fixation significantly andthe degree and duration of the suppression were related to the amount ofthe nitrogen application.更多还原