ISHS Acta Horticulturae 109: III International Symposium on Flower Bulbs
PRECONDITIONING, MEMBRANE LIPID STRUCTURE, COMPOSITION AND FLOWER QUALITY OF TULIP BULBS IN RELATION TO COLD TREATMENT |
| Authors: | J.N. Davies, G.E. Hobson |
| Abstract:
The cold requirement of tulip bulbs was satisfied by a variety of low temperatures applied to dry or planted bulbs, followed by forcing at 18°C. The degradation of starch and mobilization of total fructose in the scales were examined in relation to flowering. Slightly sub-zero temperatures were not harmful to any bulbs acclimatized to cold by successive reductions of temperature. Exposure to -20°C for brief periods even after preconditioning was generally fatal. Mitochondria were prepared from cooled and uncooled bulbs, and the upper and lower transition temperatures of their lipids were found, but the lower limit for uncooled bulbs gave an indication of falling to sub-zero temperatures more slowly than that for cooled bulbs. The results suggest that moderately low temperatures more quickly enable tulip bulbs to survive even lower temperatures through a reduction in the lower transition temperature of the membrane lipids without loss of flower quality. | |
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