大豆鼓粒期对肥料氮的吸收与分配研究

Study on fertilizer-N absorption and distribution of soybean [Glycine max (L).] during the seed-filling period

采用15N分阶段标记的方法,研究了鼓粒期间大豆植株对氮素的同化吸收,尤其是肥料氮在各器官中的积累与分配。结果表明:1)5次标记试验期间积累的氮素总量为291.4 mg/plant,占标记试验Ⅴ结束时(鼓粒末期)大豆植株氮素积累总量的48.9%,说明鼓粒期间的氮素积累对于大豆氮素积累具有重要作用;2)从鼓粒始期到鼓粒末期,大豆植株氮素阶段积累量急剧降低,由标记试验Ⅰ的109.5 mg/plant下降到标记试验Ⅴ的19.6 mg/plant;3)鼓粒期大豆植株所吸收的氮素主要来自根瘤固氮,该部分氮占总同化量的67.4%,而肥料氮只占32.6%;4)根瘤固氮和肥料氮的同化量均随着鼓粒进程的推进而下降,分别由标记试验Ⅰ的67.5和42.0 mg/plant下降到标记试验Ⅴ的10.8和8.8 mg/plant;5)5次标记试验中,不同器官中肥料氮的积累量均表现出一致的规律性,为子粒>叶片>茎>根系>荚皮,并且分配到子粒中的肥料氮比例是逐渐增加的,由标记试验Ⅰ的27.9%增加到标记试验Ⅴ的85.0%。

This experiment was conducted by using15N labeling method with staged design to study nitrogen assimilation and absorption by the soybean plant during the seed-filling period,especially the distribution of fertilizer N among different organs of soybean.The results show that total nitrogen accumulation during the five labeling experiments（0-25 d after beginning of seed-filling） plays an important role in nitrogen accumulation in soybean plant,which is about 291.4 mg/plant,occupies 48.9% to the total nitrogen accumulation in the labeling experiment Ⅴ.The nitrogen accumulation is decreased sharply during the seed filling period,which is from 109.5 mg/plant in the labeling experiment Ⅰ（0-5 d after beginning of seed-filling） to 19.6 mg/plant in the labeling experiment Ⅴ. Nodulation-N is the main source of the plan assimilated N,which is about 67.4%,and nodulations-N accumulation is decreased from 67.5 mg/plant in the labeling experiment Ⅰ to 10.8 mg/plant in the labeling experiment Ⅴ.Fertilizer-N accumulation is also decreased with the seed-filling process,from 42.0 mg/plant in the labeling experiment Ⅰ to 8.8 mg/plant in the labeling experiment Ⅴ.Fertilizer-N accumulation in different organs of soybean in different labeling experiments exhibits the same orders： seedsleavesstemsrootspod walls,and the proportion of seed N accumulation from the fertilizer is increased from 27.9% to 85.0% during the labeling period.