Variation for N Uptake System in Maize: Genotypic Response to N Supply
AuthorGarnett, T; Plett, D; Conn, V; Conn, S; Rabie, H; Rafalski, JA; Dhugga, K; Tester, MA; Kaiser, BN
Source TitleFrontiers in Plant Science
PublisherFRONTIERS MEDIA SA
University of Melbourne Author/sPlett, Darren
AffiliationAgriculture and Food Systems
Document TypeJournal Article
CitationsGarnett, T., Plett, D., Conn, V., Conn, S., Rabie, H., Rafalski, J. A., Dhugga, K., Tester, M. A. & Kaiser, B. N. (2015). Variation for N Uptake System in Maize: Genotypic Response to N Supply. FRONTIERS IN PLANT SCIENCE, 6 (NOVEMBER), https://doi.org/10.3389/fpls.2015.00936.
Access StatusOpen Access
An understanding of the adaptations made by plants in their nitrogen (N) uptake systems in response to reduced N supply is important to the development of cereals with enhanced N uptake efficiency (NUpE). Twenty seven diverse genotypes of maize (Zea mays, L.) were grown in hydroponics for 3 weeks with limiting or adequate N supply. Genotypic response to N was assessed on the basis of biomass characteristics and the activities of the nitrate ([Formula: see text]) and ammonium ([Formula: see text]) high-affinity transport systems. Genotypes differed greatly for the ability to maintain biomass with reduced N. Although, the N response in underlying biomass and N transport related characteristics was less than that for biomass, there were clear relationships, most importantly, lines that maintained biomass at reduced N maintained net N uptake with no change in size of the root relative to the shoot. The root uptake capacity for both [Formula: see text] and [Formula: see text] increased with reduced N. Transcript levels of putative [Formula: see text] and [Formula: see text] transporter genes in the root tissue of a subset of the genotypes revealed that predominately ZmNRT2 transcript levels responded to N treatments. The correlation between the ratio of transcripts of ZmNRT2.2 between the two N levels and a genotype's ability to maintain biomass with reduced N suggests a role for these transporters in enhancing NUpE. The observed variation in the ability to capture N at low N provides scope for both improving NUpE in maize and also to better understand the N uptake system in cereals.
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