Lower grain nitrogen content of wheat at elevated CO2 can be improved through post-anthesis NH4 + supplement

Research output: Contribution to journalArticlepeer-review


  • Nimesha Fernando
  • Naoki Hirotsu
  • Joe Panozzo
  • Robert M. Norton
  • Saman Seneweera

Colleges, School and Institutes

External organisations

  • University of Melbourne
  • Toyo University
  • International Plant Nutrition Institute
  • University of Southern Queensland
  • Department of Economic Development


We test the hypothesis that reduction in grain N concentration under elevated CO2 concentration (e[CO2]) is associated with N types (NH4 + and NO3 ) and their ratios. Wheat (Triticum aestivum L. cv. H45) was grown in a glasshouse under two CO2 concentrations (389 μmol mol−1 and 700 μmol mol−1), supplied with equal amount of N with different ratios of NH4 + and NO3 : (i) 100% NO3 –N; (ii) 50% NO3 –N and 50% NH4 +–N; and (iii) 25% NO3 –N and 75% NH4 +–N. Plant growth, N uptake and partitioning were measured during plant development. Plant biomass and grain yield was increased at e[CO2] when N was supplied as an equal proportion of NO3 and NH4 +. Despite the yield increment, grain N concentration was not affected by e[CO2], in 50% NO3 –N treatment. In contrast, grain N concentration decreased in 100% NO3 –N and 25% NO3 –N treatments. In 50% NO3 –N treatment, N uptake during post-anthesis stage (from 69 to 141 days after planting) was significantly stimulated under e[CO2] compared to 100% NO3 –N and 25% NO3 –N treatments. We concluded that supplement of N in an equal proportion of NO3 and NH4 + which increases post-anthesis N uptake, avoid the reduction of grain N concentration under e[CO2].


Original languageEnglish
Pages (from-to)79-85
Number of pages7
JournalJournal of Cereal Science
Early online date18 Jan 2017
Publication statusPublished - 1 Mar 2017


  • Elevated atmospheric CO, Grain nitrogen, Nitrate to ammonium ratio, Wheat

ASJC Scopus subject areas