Nitrogen is an important element for all living beings because it is part of macromolecules as significant
as nucleic acids or amino acids. For plants, it constitutes a limiting factor in their growth and development1
due to their low natural availability in soils thus limiting primary production in ecosystems2.
Conifers are a group of gymnosperm plants that form large forest extensions of vegetation, being the main
constituents of forests in boreal ecosystems3 where ammonium is the main source of inorganic nitrogen4.
Due to the characteristics of the soils in which conifers usually grow, these plants have developed a high
tolerance to the presence of ammonium, which may constitute their main source of inorganic nitrogen5.
The maritime pine (Pinus pinaster Aiton) is a conifer that has a wide distribution in the western
Mediterranean area and has been widely used in reforestation, soil stabilization tasks and industrially. In
recent years, maritime pine has been the subject of multiple omic studies that have resulted in the
acquisition of important tools and resources6,7.
The present work is focused on the analysis of the ammonium uptake and management efficiency, and its
relationship with the biomass accumulation in maritime pine. For this purpose, several experiments have
been developed in which pine seedlings have undergone different levels of ammonium nutrition, both in the
short and long term. As a result of short-term experiments, the characterization of transcriptomic response
to the process of ammonium nutrition (uptake and assimilation) is being studied at mRNA, lncRNA and
miRNA level in roots. In relation to long-term experiments, ten different provenances of maritime pine
seedlings were treated with different ammonium levels and the biomass changes were measured. The results
obtained suggest the existence a certain phenotypic plasticity grade for this conifer.
