Effect of Chilling Temperatures upon Cell Cultures of Tomato.

The effect of chilling temperatures upon cell cultures of tomato (Lycopersicon esculentum Mill cv ;VF36,' and cv ;VFNT Cherry,' and L. hirsutum Humb. & Bonpl.) was tested. Doubling times for L. esculentum were 2 to 3 days at 28 degrees C, and 3 to 8 days at 12 degrees C. No growth was observed at 8 degrees C, indicating an abrupt limit to growth between 8 and 12 degrees C. Fluorescein diacetate staining indicated that 80 to 90% of the cells were alive when cells were maintained at 8 degrees C for up to 2 weeks. When cultures kept at 8 degrees C for up to 30 days were transferred to 28 degrees C, growth resumed quickly, and at a rate virtually identical to that for unchilled cells. Similar results were found for cells maintained at 0 degrees C, and for cells of ;VFNT Cherry' and of L. hirsutum. Under certain conditions, cultures slowly doubled in fresh weight and cell volume at 8 or 9 degrees C but additional growth at 8 degrees C did not occur, nor could growth be maintained by subculture at 8 or 9 degrees C. The results are contrary to reports that cell cultures of tomato die when exposed to temperatures below 10 degrees C for 1 or 2 weeks. Our observations indicate that chilling temperatures quickly inhibit growth of tomato cells, but do not kill them.