RESPIRATION OF FLOWER BULBS: INFLUENCE OF CULTIVAR, TEMPERATURE, WOUNDING, BULB SIZE AND ETHYLENE
The literature on flower bulb respiration is relatively slim. We have conducted a series of experiments to characterize bulb respiration rates of a range of tulip, narcissus and hyacinth cultivars, and under different environmental conditions. Measurements were made in October-December, using bulbs imported from The Netherlands that were held ventilated at 17C until use. As expected, resting respiration rates (CO2 production) varied significantly by cultivar, ranging from 10-18, 9-15 and 12-35 ml/kg/h for hyacinth, narcissus and tulip bulbs, respectively. In bulbs of two tulip cultivars, respiration increased dramatically as temperature increased from 4 to 30°C. Following 2 weeks exposure to 10 µl/L ethylene (Oct.-Nov.), respiration was initially greater (52%, averaged over 14 cultivars) compared with non-ethylene treated tulip bulb. In the 6-8 days following treatment, respiration of ethylene-treated bulbs decreased to that of control bulbs, but not in all cultivars. In Bright Parrot, ethylene exposed bulbs maintained 44% greater respiration for at least 16 days after ethylene treatment ended. When Foxtrot tulip bulbs were wounded by dropping them 3 times onto a solid surface from 85 cm, respiration doubled within 2-3 hours, and remained elevated (2 to 2.5-fold higher) until the experiment was concluded after 24 days. Respiration rate was not significantly different between smaller and larger (26.3 vs. 36.5 g per bulb) Foxtrot bulbs collected from the same lot.
Miller, W.B., Pepping, M., Suazo, G. and Wanxiang Lu, (2013). RESPIRATION OF FLOWER BULBS: INFLUENCE OF CULTIVAR, TEMPERATURE, WOUNDING, BULB SIZE AND ETHYLENE. Acta Hortic. 1002, 365-372
carbon dioxide, Hyacinthus, Narcissus, Tulipa