Ethylene Binding to Senescing Carnation Petals

Brown, J. H., Legge, R. L., Sisler, E. C, Baker, J E. and Thompson,J. E. 1986. Ethylene binding to senescing carnation petals.—J.exp. Bot 37: 526–534. Ethylene binding to carnation petals is significantly higheron a fresh weight basis for young fully expanded flowers thanfor older flowers showing petal-inrolling symptoms. The peakin ethylene binding precedes the climacteric-like rise in ethyleneproduction even when production of endogenous ethylene is inhibitedby incorporating amino-oxyacetic acid into the petals. FromScatchard analyses of ethylene binding, it has been estimatedthat petals from young fully expanded flowers have 11?10⁴ bindingsites per cell, whereas petals from senescent flowers showingextensive petal inrolling have 0.6?1010⁴ binding sites per cell.It is also apparent from the Scatchard analyses that the affinityof binding sites for ethylene decreases with advancing age ofthe flowers. The decline in number of binding sites with advancingage can be essentially accounted for by the extensive breakdownof membranes that accompanies senescence. However, the decreasedaffinity for ethylene in the older tissue suggests that thebinding sites become altered with advancing senescence. Key words: Carnation, ethylene binding, senescence