Nitrogen Metabolism and Biomass Production in Forest Trees

Abstract

Low nitrogen (N) availability is a major limiting factor for tree growth and development. N uptake, assimilation, storage and remobilization are key processes in the economy of this essential nutrient, and its efficient metabolic use largely determines vascular development, tree productivity and biomass production. Recently, advances have been made that improve our knowledge about the molecular regulation of acquisition, assimilation and internal recycling of N in forest trees. In poplar, a model tree widely used for molecular and functional studies, the biosynthesis of glutamine plays a central role in N metabolism, influencing multiple pathways both in primary and secondary metabolism. Moreover, the molecular regulation of glutamine biosynthesis is particularly relevant for accumulation of N reserves during dormancy and in N remobilization that takes place at the onset of the next growing season. The characterization of transgenic poplars overexpressing structural and regulatory genes involved in glutamine biosynthesis has provided insights into how glutamine metabolism may influence the N economy and biomass production in forest trees. Here, a general overview of this research topic is outlined, recent progress are analyzed and challenges for future research are discussed.

Effects of Phosphate-Solubilizing Bacteria and N2-fixing Bacteria on Nutrient Uptake, Plant Growth, and Bioactive Compound Accumulation in Cyclocarya paliurus (Batal.) Iljinskaja

“…It is known that plant secondary metabolites could be induced by adverse environmental conditions and regulated by internal nutrients balance [41]. Previous studies indicated that C, N, S, and P contents in plants were related to both primary growth and secondary metabolites [44,45]. Xie et al reported that the improved root P status to arbuscular mycorrhizal fungi could affect plant C balance and induce more C partitioning to secondary metabolism [46].…”

Seasonal nitrogen remobilization and the role of auxin transport in poplar trees

“…Because seasonal N cycling occurs annually in deciduous forest trees, N is retained and reused for longer periods of time ( Millard et al , 2006 ; Millard and Grelet, 2010 ) which contributes to the economics of N use and provides a competitive advantage in N-limited conditions ( Chapin et al , 1990 ; Millard and Grelet, 2010 ). Consequently, seasonal N cycling is a major factor for N-use efficiency (NUE) ( Vitousek, 1982 ; Chapin and Kedrowski, 1983 ; Aerts, 1990 ; Cánovas et al , 2018 ), and is an important trait in the development of perennial lignocellulosic energy feedstocks ( Karp and Shield, 2008 ; Allwright and Taylor, 2016 ). Despite the importance of seasonal N cycling to N allocation and partitioning, the contribution of stored N to growth and the mechanisms involved in source to sink remobilization of stored N remain poorly understood in trees.…”

Association of spectroscopically determined leaf nutrition related traits and breeding selection in Sassafras tzumu

“…Nitrogen (N) is one of the most essential nutrients in plant growth, which is needed for the improvement of grain yield and quality [ 10 ]. Excessive N fertilizer application creates severe environmental problems, while inadequate N availability limits productivity.…”