Our research group focusses on different fields of research, e.g. phloem loading in plants, analyses of nectar and crops.
2. Phloem loading in trees
Little is known about transport sugars in the phloem of trees. Also the possible mechanisms of phloem loading have hardly been explored in woody plants. Therefore these two questions will be investigated in a research project including diverse deciduous trees (e.g. Quercus robur, Fraxinus excelsior) and different gymnosperm tree species. In these tree species it could be shown so far that phloem loading has to be an active process due to the existence of a high concentration gradient of transport sugars between mesophyll cells and the phloem. Active phloem loading is mediated by proton-sucrose symporters (SUTs). Furthermore, the influence of family affiliation and different environmental conditions is investigated.
3. Regulation of the nectar composition
The evolutionary success of the flowering plants is often attributed to their numerous mutualistic relationships with their pollinators. Plant species and their particular pollinators are often highly adapted to each other. From all attraction mechanisms floral nectar seems to be the most impotant one. Different ecological, physiological, co-evolutionary and phylogentical factors that affect the nectar composition are examined especially in the families of Bromeliaceae, Onagraceae and the genus Nicotiana. Additionally to the „big three“ (Sucrose, Glucose and Fructose) many more compounds are analysed. Furthermore to origin of the nectar compounds is studied, e.g. by comparing the compounds of the phloem with the nectar.
4. Analysis of modified crops
Numerous demands are made on crops: among other things they have to be profitable and adapted to biotic and abiotic stresses. Therefore the change in characteristics of crops is an on-going process. In this context different aspects need to be examined: Which organic carbon and nitrogen compounds are transported via phloem and how much is this process influenced by environmental factors? What is the correlation between the glucosinolate content and the sugar metabolism in different rape genotypes? What role do sucrose transporters play for the phloem loading in corn?