Nitrogen uptake and assimilation during Norway spruce somatic embryogenesis

Sweden is currently experiencing shortage of Norway spruce (Picea abies) seeds due to e.g. irregular flowering and the recent year’s outbreaks of pests and pathogens destroying cones and seeds. Therefore, the forest sector is investigating alternative ways of propagating Norway spruce plants to secure Norway spruce regeneration and sustain the genetic diversity. Somatic embryogenesis (SE) is a vegetative method that can be used for in vitro propagation of Norway spruce plants. Plants produced through the SE technique could potentially lead to; i) shorter time from recent tree breeding improvements to reforestation. ii) preserving genetic diversity in managed forests, while maintaining genetic gains from the tree breeding. SE can also be used as a mean to cryo-preserve valuable genetic material and to study embryo development. Unlike the seed embryo development, which is dependent on the surrounding tissue for nutrients, the entire SE development is undeniably dependent on the culture conditions; light, temperature, gaseous environment, media amendments and nutrient composition. I have used SE as a research tool to generate material for studying uptake, and utilization of carbon and nitrogen during Norway spruce embryo development. My research has contributed new evidence that media supplied glutamine is essential for growth during the process of Norway spruce somatic embryogenesis. I found that media supplied with glutamine is important for maintaining the pool of free amino acids, the building blocks of e.g. DNA, proteins and chlorophyll. In addition, glutamine present in the growth medium assisted in alleviating stress-related metabolic pathways - the alanine aminotransferase pathway and the GABA shunt. Furthermore, the findings from my work can aid the on-going development for an industrial production system for Norway spruce plants through SE. My research project has been a collaboration between Swedish university of agricultural science (SLU) and the forest company Sveaskog, specifically the seed and plant division Svenska Skogsplantor