https://search.dev.ndltd.org/etd/massey/oai:mro.massey.ac.nz:10179/4229
type: CreativeWork
name: Ethephon, ethylene and abscission physiology of camellia : a thesis presented in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Horticultural Science at Massey University, Palmerston North, New Zealand
description: Ethylene application to leaves and floral buds of Camellia resulted in abscission with a lag period, the duration of which was dependent on ethylene concentration and cultivar. During this period, cellulase activity doubled in leaf abscission zones, and when abscission commenced, activity increased more rapidly. However, no increase in cellulase activity was observed in floral bud abscission zones. Propylene application revealed that autocatalytic ethylene production increased in leaf abscission zones prior to and decreased after abscission. However, in the leaf blade, no change in endogenous ethylene production was measured, nor were any signs of leaf senescence observed. Application of(STS) completely inhibited leaf abscission and delayed and reduced floral bud abscission in response to applied ethylene. This pointed to a similar role for ethylene in both organs, but that the abscission process of floral buds occurred at a faster rate than that of leaves. Application of ethylene for differing durations to floral buds and leaves demonstrated that regardless of ethylene treatment duration, abscission ceased less than 24 hr after ethylene removal indicating that continuous ethylene exposure is required to promote abscission of Camellia organs. Measurement of abscission rate (time to 50% abscission) in response to a range of ethylene concentrations determined that floral buds were more sensitive (that is; responded more rapidly to lower ethylene concentrations) than leaves. Ethylene-sensitivity was i nfluenced by organ maturity. As floral buds mature d from initiation t o flower opening, the rate of ethylene-promoted abscission i ncreased, i ndicati ng g reater sensitivity. Leaves were most sensitive to ethylene directly after bud break and sensitivity decreased untiiU weeks after cessation of stem extension ; after this time, sensitivity did not change significantly over the next 3 years. Low temperatures reduced the ethylene-promoted abscission rate of both leaves a…
abstract: Ethylene application to leaves and floral buds of Camellia resulted in abscission with a lag period, the duration of which was dependent on ethylene concentration and cultivar. During this period, cellulase activity doubled in leaf abscission zones, and when abscission commenced, activity increased more rapidly. However, no increase in cellulase activity was observed in floral bud abscission zones. Propylene application revealed that autocatalytic ethylene production increased in leaf abscission zones prior to and decreased after abscission. However, in the leaf blade, no change in endogenous ethylene production was measured, nor were any signs of leaf senescence observed. Application of(STS) completely inhibited leaf abscission and delayed and reduced floral bud abscission in response to applied ethylene. This pointed to a similar role for ethylene in both organs, but that the abscission process of floral buds occurred at a faster rate than that of leaves. Application of ethylene for differing durations to floral buds and leaves demonstrated that regardless of ethylene treatment duration, abscission ceased less than 24 hr after ethylene removal indicating that continuous ethylene exposure is required to promote abscission of Camellia organs. Measurement of abscission rate (time to 50% abscission) in response to a range of ethylene concentrations determined that floral buds were more sensitive (that is; responded more rapidly to lower ethylene concentrations) than leaves. Ethylene-sensitivity was i nfluenced by organ maturity. As floral buds mature d from initiation t o flower opening, the rate of ethylene-promoted abscission i ncreased, i ndicati ng g reater sensitivity. Leaves were most sensitive to ethylene directly after bud break and sensitivity decreased untiiU weeks after cessation of stem extension ; after this time, sensitivity did not change significantly over the next 3 years. Low temperatures reduced the ethylene-promoted abscission rate of both leaves a…
author: Woolf, Allan Brian
keywords: Camellia, Ethylene, Abscission
date published: 1992
date modified: 2026-07-27T20:18:10Z
provider: Massey University
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: Massey University