Aim of this project is the investigation of biochemical regulatory steps of the carbohydrate metabolism which influence the delivery of substrates for the biosynthesis of isoprene and monoterpenes in leaf mesophyll cells of different tree species. The data obtained within the frame of the TFS indicate, that the parameters determined up to now (ATP/ADP ratio; redox charge, pool sizes of carbohydrates and sugar phosphates, etc.) form an important basis for the further development and validation of a process-oriented emission model. The following aspects are pursued (daily courses under given environmental and controlled conditions):

• determination of pool sizes of the substrates of the synthesis of isoprene (glyceraldehyde phosphate, pyruvate)
• determination of pool sizes of compounds with regulatory function or acting as carbon sources for the biosynthesis of isoprenoids (NADP, NADPH, ATP, ADP, fructose-2.6-bisphosphate, triosephosphates, 3-phosphoglyceric acid, phospho-glycolate, ribulose-1.5-bisphosphate, sucose, starch)
• determination of carbon fluxes by means of 14C tracer studies
• determination of extractable acitivities and of the state of activation of key enzymes of starch and sucrose synthesis (ADPglucose pyrophosphorylase; sucrose phosphate synthase)
• validation of data obtained by the investigation of model plants with isoprene-emitting broadleaf trees (Quercus pubescence, Populus spec., Salix spec) and monoterpene-emitting species such as Quercus petraea or Norway spruce.