PLANT PHYSIOLOGY , Vol 109, Issue 4 1219-1225, Copyright © 1995 by American Society of Plant Biologists
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WHOLE PLANT, ENVIRONMENTAL, AND STRESS PHYSIOLOGY |
The Role of Ethylene in Interorgan Signaling during Flower Senescence
E. J. Woltering, D. Somhorst and P. van der Veer
Agrotechnological Research Institute (ATO-DLO), P.O. Box 17, 6700 AA Wageningen, The Netherlands
The roles of 1-aminocyclopropane-1-carboxylic acid (ACC) and ethylene in
interorgan signaling during senescence in orchid (Cymbidium) flowers were
investigated. Following application of radiolabeled ACC to the stigma or
the rostellum (modified lobe of the stigma), radiolabeled ethylene is
produced by all flower parts. In intact flowers as well as in excised
central columns, stigma- or rostellum-applied ACC or
[alpha]-aminoisobutyric acid were largely immobile. Local treatment of the
central column of previously aminoethoxyvinylglycine-treated flowers with
either ethylene or 2-chloroethylphosphonic acid (ethephon) rapidly induced
emission of ethylene from the petals, showing that ethylene is readily
translocated within the flower. Creation of alternative outlets (incisions)
in the labellum or the central column significantly delayed the occurrence
of senescence symptoms in ACC-treated flowers. The results do not confirm
the presumed role of ACC as a signal in interorgan communication during
flower senescence. In these flowers, ethylene produced in the stigmatic
region following pollination or emasculation serves as a mobile factor
responsible for senescence symptoms observed in other flower parts.
