Effect of culture container and carbohydrate content on in vitro slow growth storage of the cherry rootstock 'Gisela®5'

Abstract The present study investigated the effects of gas- tight and gas-permeable culture containers and different sucrose concentrations, as well as sucrose and mannitol combinations on the development of an effective in vitro slow growth storage protocol (at 4 °C, in darkness) for 'Gisela®5' shoot cultures. 'Gisela®5' is the most widely used cherry rootstock in Europe. This dwarf triploid hybrid has many advantages over the conventional cherry root- stocks. Optimizations for the cold storage of 'Gisela®5' in vitro shoot cultures included use of storage medium supplemented with 10, 20, 30, 45, and 60 g L-1 sucrose and sucrose (15, 30 g L-1) and mannitol (15 g L-1) combinations, contained in gas-tight glass jars and gas- permeable 'Star PacTM' bags. Cold storage was prolonged to 12 months, during which in every 3 months, cultures were evaluated. Possibility of 16 month-cold storage in gas-tight glass jars was also explored, during which gas chromatographic analysis was performed for the detection of CO2 and ethylene accumulation for the first 5 months of cold storage. Our results showed that both the 12- and 16-month conservations were possible, especially when 45 or 60 g L-1 sucrose was supplemented to storage medium, contained in glass jars. Mannitol inclusion to the storage medium was also effective to reduce the metabolic activity of the shoot cultures during storage; however, it did not have a significant positive influence on shoot quality in post-conservation.