Nitrogen nutrition in plants: rapid progress and new challenges

As a main feature of plant autotrophy, assimilation of inorganic nitrogen is not only of fundamental scientific interest, but also a crucial factor in crop productivity. In its broad sense - from root uptake of various forms of N in the soil to allocation of N assimilates to different organs - it involves a wide range of physiological processes whose mechanisms are far from being fully understood. The aim of this special issue is to provide a wide overview of recent progress in this field, and to draw an interdisciplinary picture of the prospects for future research.