Chin J Plan Ecolo ›› 2008, Vol. 32 ›› Issue (6): 1407-1416.DOI: 10.3773/j.issn.1005-264x.2008.06.022

• Research Articles • Previous Articles     Next Articles

EFFECTS OF NITROGEN LEVEL ON NITROGEN METABOLISM AND CORRELATING ENZYME ACTIVITY IN PEANUT

ZHANG Zhi-Meng1; WAN Shu-Bo2*;NING Tang-Yuan3; DAI Liang-Xiang1   

  1. 1Peanut Research Institute of Shandong Province, Qingdao, Shandong 266100, China;2Shandong Academy of Agricultural Sciences, Jinan 250100, China;3State Laboratory of Crop Biology, College of Agronomy, Shandong Agricultural University, Taian, Shandong 271018, China
  • Online:2008-11-30 Published:2008-11-30
  • Contact: WAN Shu-Bo

Abstract: Aims Nitrogen is very important for improving the yield and quality of peanut. Nitrate reductase (NR), glutamine synthetase (GS) and glutamate dehydrogenase (GDH) are the main enzymes of nitrogen metabolism that would be affected by nitrogen level. Our objective was to study the effects of nitrogen level on soluble protein content, free amino acid content and correlating enzyme activities of nitrogen metabolism in peanut.
Methods We carried out a field experiment of two cultivars under four nitrogen levels (0, 45, 90 and 180 N kg•hm–2) and investigated the soluble protein content and free amino acid content in leaf, stem, root and pod of peanut, as well as the activities of the nitrate reductase (NR), glutamine synthetase (GS) and glutamate dehydrogenase (GDH) in these organs.
Important findings With the nitrogen application, the soluble protein content and free amino acid content were increased, and the activities of the nitrate reductase (NR), glutamine synthetase (GS) and glutamate dehydrogenase (GDH) also increased. When excessive nitrogen was used, the NR activity and kernel protein content were increased, while the activities of GS and GDH were decreased. Soluble protein content, free amino acid content, NR, GS and GDH along with the growth periods were not affected by nitrogen level, but with suitable nitrogen the activities of NR and GS in different organs could be increased. Also, nitrogen level affected GDH activities in leaf and kernel, with lower effect on the GDH activities in stalk and root. In conclusion, nitrogen level could affect the correlating enzyme activities of nitrogen metabolism in peanut, which resulted in changes of soluble protein content and free amino acid content in organs. The best nitrogen level for peanut was 90 N kg•hm–2.