Ammonium and urea based nutrition turns stressful to plant species, including important crops. One of the most dramatic plant adaptations to ensure adequate nitrogen acquisition is the modulation of root system architecture (RSA) in response to nitrogen supply. Besides, the effect of oximes in the development of this RSA is unknown. Therefore, the objective of this work was to study the dynamic phenotyping of Medicago truncatula roots during plant development under different nitrogen-based nutrition (either nitrate, ammonium or urea) in axenic conditions with the application of indole-3-acetaldoxime (IAOx) and indole-3-acetic acid (IAA). Medicago truncatula seeds were germinated in agar plates containing Fahraeus medium with phytagel, as nutrient solution. The quantification of root growth and architecture was performed with the semi-automated image analysis software SmartRoot1 by estimating growth rates, lateral root density and branching angles. Root system was photographed each 2 days during 15 days. A dataset was established containing a whole architectural description of the RSA under the different N sources and the effect of the oximes. Our results indicate that important changes occurred in the development and architecture of root system due to the effect of IAA and IAOx. This systematic comparison of RSA responses to nutrient provides a comprehensive view on the overall changes in root plasticity providing a solid basis for the identification of regulatory steps in the root developmental program. This, together with an increased understanding of mechanisms underpinning efficient N uptake and throughput tools to phenotype these traits will help breeders achieve this goal.

Trabajo presentado en el Plant Biology Eudrope EPSO / FESPB Congress, celebrado en Praga (República Checa) del 26 al 30 de junio de 2016

Peer reviewed