Nitrogen is an essential element for plant growth. During the green revolution nitrogenfertilisation was responsible for spectacular yield increases. At present yield is balanced with commitments towards the environment and sustainable agriculture. For agro-biotechnology comprehensive knowledge of plant functioning is needed. Yield improvement and accumulation of essential nitrogen compounds is relying on selection and gene technologies.Research on the uptake, acquisition and assimilation of nitrogen, as well as the synthesis and storage of reserve and defence N-compounds, therefore, is essential. The third volume in the Plant Ecophysiology series integrates functional and molecular physiology with ecophysiological and sustainable agricultural approaches to get a better understanding of the regulation and the impact of environmental and stress signals on nitrogen acquisition and assimilation. The book is of interest for advanced students and junior researchers and supplies comprehensive information for scientists working in the field of nitrogen metabolism and readers interested in sustainable development.