CHANGES IN RESPIRATORY CHARACTERISTICS AND ETHYLENE PRODUCTION IN TULIP BULBS AFTER COLD TREATMENT

W.A. Kanneworff, L.H.W. van der Plas
During the 1988/1989 season the effect of 5°C cooling on tulip bulbs was studied. To correct for seasonal changes 4 different series of 5°C cooling were started. Each series was monitored for 16 weeks. During this period several samples were taken. From these sampled bulbs mitochondria were isolated. To characterize mitochondria state 3, alternative pathway capacity and RC were measured. To investigate the effect of transfer to 17°C after cooling, bulbs from all series were placed at 17°C after various periods of storage at 5°C. From these bulbs also mitochondria were isolated and characterized after 1–9 days at 17°C.

Mitochondrial characteristics of transferred bulbs cooled for a long period before transfer differed from those only cooled for a short period. After a long 5°C pretreatment succinate state 3 and RC values showed a decline, in contrast with bulbs only cooled for a short period. Alternative pathway capacity did not show such a relation with the length of the period of cooling.

Parallel to these measurements of mitochondrial respiration the ethylene production of intact bulbs was studied. Ethylene production by tulip bulbs was very low (1–35 nl C2H4 [h]-1 [kg FW]-1). For all 4 series we found a gradual rise in ethylene production during cold storage. At the end of the season more ethylene was produced in control bulbs stored at 17°C than in 5°C bulbs.

To check the effect of the length of the cooling period on flowering, bulbs from all series were planted in a glasshouse after various periods of cooling at 5°C. Within one series, flowerstalks of 11, 12 and 13 weeks 5°C cooled bulbs were comparable in length but this length gradually decreased in the season. In the last series 9 and 16 weeks 5°C bulbs had shorter flowerstalks than 11–13 weeks cooled bulbs. This was in contrast with the first two series where lengths from 9–16 weeks cooled bulbs showed no significant differences.

Kanneworff, W.A. and van der Plas, L.H.W. (1990). CHANGES IN RESPIRATORY CHARACTERISTICS AND ETHYLENE PRODUCTION IN TULIP BULBS AFTER COLD TREATMENT. Acta Hortic. 266, 229-236
DOI: 10.17660/ActaHortic.1990.266.29
https://doi.org/10.17660/ActaHortic.1990.266.29

Acta Horticulturae