S19 - Session O6 - 11C-Photosynthate translocation to strawberry fruits depends on leaf transpiration

Authors: Jens Mincke *, Yuta Miyoshi, Jan Courtyn, Stefaan Vandenberghe, Christian Vanhove, Kathy Steppe

Worldwide, strawberry plants ( Fragaria × ananassa Duch.) are cultivated in large quantities for their fruits, that are widely cherished for their juicy texture, bright red colour, distinctive aroma, and sweetness. These attributes play an essential role in overall quality of strawberry fruits and can directly be related to the presence of sugars (and derivatives thereof) and acids. Hence, environmental control based on photosynthate translocation is indicative for realising high-yield and high-quality production. Studies on the environmental response of photosynthate translocation are, however, scarce. We applied the medical imaging technique positron emission tomography (PET) to visualize photosynthate transport to strawberry fruits in vivo while focussing on light intensity as a key environmental factor to steer translocation. To this end, a leaf of intact strawberry plants was fed with 11 CO 2 and real-time dynamics of 11 C-labeled photosynthate translocation to individual fruits was analysed using PET under different light intensities (50, 200 and 400 μmol m -2 s -1 ). Highest translocation rates into strawberry fruits were found under a light intensity of 200 μmol m -2 s -1 followed by those of 400 and 50 μmol m -2 s -1 , suggesting an incoherent relation of light intensity and 11 C-photosynthate translocation. However, a strong negative correlation between leaf transpiration of the 11 C-fed source leaf and 11 C-photosynthate translocation rate existed. These novel findings indicate that leaf transpiration is one of the main drivers for photosynthate translocation towards fruits.