Jump to Main Content
The control of flower senescence in petunia (Petunia hybrida)
- Lovell, P.J., Lovell, P.H., Nichols, R.
- Annals of botany 1987 v.60 no.1 pp. 49-59
- Petunia hybrida, styles, 2,4-D, flowers, corolla, senescence, wilting, abscission, pollination, stigma, carboxylic acids, thiosulfates, ethylene production
- Petunia corollas wilt and abscise between one and two weeks after detachment when maintained in distilled water in vials at 18 °C. The onset of wilting is brought forward substantially by the application of 1-aminocyclopropane-1-carboxylic acid (ACC) either to the vial solution or to the stigmatic surface. Both pollination and stigma removal also shorten the time to the onset of wilting, colour change and to abscission. In the case of stigma removal, the life span of the corolla is shortest when the treatment is made at the time of flower detachment (day 0), whereas pollination has the greatest effect if it occurs on day 1. Stigma damage still has an effect on corolla senescence even when stigma and style are removed, as long as they have been left in place for a few hours after treatment. Evidence from several experiments shows that a 17 h period is sufficient for the full effect to be shown, and that probably there are some effects on the corolla even if the damaged stigma is only left in position for 3–6 h. Treatments which advance corolla death (to day 3) also advance the peak of ethylene production by the pistil (to day 1) and the corolla (to day 2). The use of silver thiosulphate (STS) overcomes all manipulative and chemical treatments used, and greatly extends vase life. The extension occurs even when STS application is delayed for 24 h, i.e. after the peak of ethylene production by the pistil and after any senescence signal has arrived at the corolla. In this case, however, the time to first morphological change is largely unaffected, but the STS greatly extends the time period between first morphological change and corolla death. The evidence suggests that early symptoms of senescence e.g. colour change and slight loss of turgor, do not automatically lead to corolla abscission.