In vitro conservation of chestnut (Castanea sativa) by slow growth

Slow growth storage has been achieved for Castanea sativa (cv. 'Montemarano') shoot cultures over a duration of 48 mo at a temperature of 8A degrees C, where 82% of explants survived and were able to resume normal growth after transfer to standard culture conditions at 23A degrees C. The evaluation of the chlorophyll content of leaves also showed no differences between material stored for 48 mo and control material subcultured at 23A degrees C. With a storage temperature of 4A degrees C, the survival of shoots was significantly lower at approximately 56% after 12 mo, and no plants recovered after 24-mo storage. The presence of 6-benzyladenine 0.44 mu M in the culture medium proved to be necessary for the recovery of healthy shoots, while pre-treatments with different concentrations of abscisic acid did not significantly influence the survival of shoots following storage conditions. A low level of light during slow growth storage resulted in positive effects on the rate of shoot survival over the longest preservation periods.