ISHS Acta Horticulturae 405: VI International Symposium on Postharvest Physiology of Ornamental Plants
CHARACTERISTICS OF PETAL SENESCENCE IN A NON-CLIMACTERIC CUT FLOWER |
| Authors: | R. Jones, R. McConchie |
| Abstract:
Studies on the physiology and molecular biology of cut flower petal senescence have mostly concentrated on climacteric flowers, and little is known of the pattern and control of petal senescence in non-climacteric flowers, such as tulips. Flower water uptake and fresh weight (FW) of attached Tulipa hybrida ‘Silentia’ petals declined rapidly from 4 days after harvest, corresponding to the onset of petal wilting. Petal respiration declined rapidly within 2 days of harvest, while ethylene production remained low, indicating this cultivar was non-climacteric. Soluble protein levels also declined significantly in the first three days after harvest. The activity of lipoxygenase (LOX), an enzyme thought to be associated with membrane degradation, was measured in Dianthus caryophyllus ‘White Sim’ petals and compared with activity in ‘Silentia’ petals during senescence. Activity in ‘White Sim’ petals reached a peak prior to wilting, thought to be concomittant with the rise in ethylene production by the petals, and then declined. In tulip petals, however, LOX activity rose significantly from harvFest and also peaked prior to the onset of petal wilting (4 days after harvest). LOX activity and wilting were significantly reduced in tulip petals treated with 1mM cycloheximide (CHI), indicating that LOX activity was dependent on protein synthesis. The data suggest that despite the lack of a respiratory climacteric and ethylene production, petal wilting in tulips is also associated with a rapid increase in de novo synthesis of LOX. | |
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