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Transition from a maternal to external nitrogen source in maize seedlings

Bibliography:

Kasra Sabermanesh, Luke R. Holtham, Jessey George, Ute Roessner, Berin A. Boughton, Sigrid Heuer, Mark Tester, Darren C. Plett, and Trevor P. Garnett. Transition from a maternal to external nitrogen source in maize seedlings. Journal of Integrative Plant Biology. DOI: 10.1111/jipb.12525

Authors:

Kasra Sabermanesh, Luke R. Holtham, Jessey George, Ute Roessner, Berin A. Boughton, Sigrid Heuer, Mark Tester, Darren C. Plett, and Trevor P. Garnett

Keywords:

Amino acids; NPF; NRT; Zea mays; nitrate uptake; nitrogen use efficiency; roots; seed; seedling

Year:

2017

Abstract:

​Maximising NO3− uptake during seedling development is important as it has a major influence on plant growth and yield. However, little is known about the processes leading to, and involved in, the initiation of root NO3− uptake capacity in developing seedlings. This study examines the physiological processes involved in root NO3− uptake and metabolism, to gain an understanding of how the NO3− uptake system responds to meet demand as maize seedlings transition from seed N use to external N capture. The concentrations of seed-derived free amino acids within root and shoot tissues are initially high, but decrease rapidly until stabili​sing eight days after imbibition (DAI). Similarly, shoot N% decreases, but does not stabilise until 12–13 DAI. Following the decrease in free amino acid concentrations, root NO3− uptake capacity increases until shoot N% stabilises. The increase in root NO3 uptake capacity corresponds with a rapid rise in transcript levels of putative NO3− transporters, ZmNRT2.1 and ZmNRT2.2. The processes underlying the increase in root NO3− uptake capacity to meet N demand provide an insight into the processes controlling N uptake.

ISSN:

1744-7909