This proceedings volume contains a selection of invited and contributed papers of the 9th International Workshop on Sulfur Metabolism in Plants, which was hosted by Heinz Rennenberg, Albert-Ludwigs-University Freiburg and was held at Schloss Reinach, Freiburg-Munzigen, Germany from April 14-17, 2014. The focus of this workshop was on molecular physiology and ecophysiology of sulfur in plants and the content of this volume presents an overview on the current research developments in this field.

Nitrogen (N) and phosphorus (P) nutrition of trees has been studied for many decades, but has largely been focused on inorganic nutrient uptake and leaf level nutrient contents. In recent years it became obvious that N and P cycling at the ecosystem level is of vital importance for tree nutrition and that organic N uptake by trees is an essential part of ecosystem N cycling; in particular on N and/or P poor soils, and in cooler climates. The significance of organic P uptake by trees is still a matter of debate, especially under field conditions. The overlay of climate change on ecosystem N...