Chinese Bulletin of Botany ›› 2015, Vol. 50 ›› Issue (4): 490-494.DOI: 10.11983/CBB14129

• EXPERIMENTAL COMMUNICATIONS • Previous Articles     Next Articles

Research into Nitrogen Application and Utilization Rate in Soybean Leaves With 15N Tracing Technique

Candong Li, Tai Guo*, Zhixin Wang, Wei Zheng, Zhenyu Zhang, Meiling Guo, Zhongtang Liu   

  1. Jiamusi Branch Academy of Heilongjiang Academy of Agricultural Sciences, Jiamusi 154007, China
  • Received:2014-07-16 Accepted:2014-12-26 Online:2015-07-01 Published:2015-05-07
  • Contact: Guo Tai
  • About author:

    ? These authors contributed equally to this paper

Abstract: To study nitrogen application and utilization rates in soybean leaves, we used the major soybean cultivar in the Sanjiang Plain of Heilongjiang province HeNong64 to analyze nitrogen accumulation and recovery rate in soybean leaves of the R5 stage with the 15N tracing technique. Dry weight and nitrogen accumulation of soybean organs were significantly higher with 4.5 kg∙hm-2 than other treatments. The dry weight of seeds was 22.7 g and the total plant dry weight was 73.2 g, which were significantly higher than without nitrogen application, by 17.92% and 16.38%, respectively. The nitrogen accumulation in seeds was 134.4 mg per plant and higher than without nitrogen application by 13.13%, so 4.5 kg∙hm-2 was the most suitable leaf nitrogen application amount for HeNong64 in the R5 stage. Under the tested nitrogen levels, 15N accumulation in different organs first increased then decreased with increasing nitrogen levels, and the 15N accumulation in seeds was the highest (9.96 mg per plant) with 4.5 kg∙hm-2 treatment. Therefore, 4.5 kg∙hm-2 was the most suitable leaf nitrogen application amount for HeNong64 and leaf nitrogen was the main source of nitrogen for seeds. Under the same nitrogen application level, 15N accumulation in different organs was in the order of seed>stem>leaf>pod> petiole>root and the nitrogen accumulation was significantly higher in seeds than in other organs in the R5 stage. The 15N contribution rate and plant nitrogen recovery rate in seeds with 3.5 kg∙hm-2 was highest, so nitrogen was easier to be absorbed with lower leaf nitrogen application, but its net accumulation was lower than 4.5 kg∙hm-2 and the plant nitrogen recovery rate was higher than 4.5 kg∙hm-2.