Osmin Torres Gutierrez1, Glenn Fitzgerald1,2, Michael Tausz3, Roger Armstrong2, Sabine Tausz-Posch1
1 Department of Agriculture and Food Systems, The University of Melbourne, 4 Water St., Creswick VIC 3363, Australia. firstname.lastname@example.org
2Agriculture Victoria, Crains Innovation Park, Private Bag 260, Horsham VIC 3401, Australia
3Department of Forest and Ecosystem Science, The University of Melbourne, 4 Water St., Creswick VIC 3363, Australia.
The atmospheric carbon dioxide concentration is increasing and is predicted to reach ~550 µmol mol-1 by 2050. As an essential resource for plant metabolism, elevated [CO2] (e[CO2]) will impact plant performance. For example, when wheat (Triticum aestivum L.) grows under e[CO2], biomass and yield are increased while grain nitrogen (N) concentration is decreased negatively affecting the nutritional quality of the grain. It has been suggested that N partitioning in plant organs and N remobilisation from vegetative plant parts to the grain is changed under e[CO2], contributing to decreased grain N under e[CO2]. The aim of this study was to investigate (1) whether targeted N fertilisation strategies can help to overcome grain N reductions under e[CO2] and (2) to evaluate the N dynamics in different plant components in response to e[CO2] conditions and contrasting N fertilisation strategies. The present study shows that biomass partitioning (leaf to stem ratio) was decreased in response to e[CO2] and increased at anthesis due to fertilisation. The N accumulation and partitioning was affected by e[CO2] in leaf and to a lesser extent in stem at anthesis but this effect was gone at maturity. The differences in N partitioning and reduced remobilisation to grain suggest a bottleneck in translocation of N that may not be solved by adding more N fertiliser to the crop under e[CO2], at least under the environmental conditions present in 2015.