Fruit development involves a plethora of processes that control phytohormone signaling and sugars transport. Deeper understanding of these processes is key to crop improvement. Whereas ripening of climacteric fruit (e.g. tomato) is characterized by a burst in ethylene production and respiration, mechanisms within non-climacteric fruit (e.g. pepper, strawberry) are still a matter of debate. This project’s first objective is to shed a light on this knowledge gap by investigating the dynamic transport of phytohormones and sugars from/to developmental organs (flowers, fruits) as well as their mutual interplay in sweet pepper (Capsicum annuum L.). Specifically, indications were found that photosynthetically-derived compounds also embody a hormone-like liability. Their synergistic/antagonistic relation with hormones will therefore be investigated. Hereby, we propose the application of radiolabeled molecules in combination with the medical imaging modality positron emission tomography (PET). PET enables visualization of in vivo experiments to spatially trace processes non-invasively. The UGent Laboratory of Plant Ecology is one of the few research groups worldwide currently specialized in plant-PET studies. For our second objective we will expand the PET experiments to study a common problem in pepper production, i.e. flower and fruit abortion. As up to 80% of the reproductive organs abort, we want to track down the underlying causes by investigating the role of hormones and sugars.