Articles
AN IN VITRO BIOASSAY FOR THE EVALUATION OF COLD TREATMENT ON FLOWER BUD DORMANCY IN CAMELLIA
Article number
961_77
Pages
607 – 611
Language
English
Abstract
Camellia japonica L. is an evergreen shrub whose cultivars are of great
ornamental value.
Initiation and early differentiation of flower buds starts from late spring on while flower bud development and visible bud enlargement sequel until autumn.
In many temperate woody ornamentals, dormancy is installed after flower bud differentiation.
The exposure of floral buds to cold temperatures (between 2-7°C) will enhance dormancy release and initiate normal growth and anthesis during the next spring.
To quantify the cold requirement five low temperature regimes,
consisting of darkness and a constant temperature of 7°C applied for 0, 2, 4, 6 and
8 weeks, were tested on budded plants of the cultivar Nuccios Pearl. As indicator of dormancy release, an inexpensive and easygoing test was conducted by forcing
excised flower buds in an in vitro bioassay.
Simultaneously a possible hormonal basis for this endodormancy was assessed by measuring the concentration of abscisic acid in floral buds.
Our results indicated that the bioassay is a suitable indicator of the moment of dormancy release as it was able to highlight a reduced amount of
dormancy when buds stayed longer at cold.
Abscisic acid content in floral buds
decreased after 6 and 8 weeks of cold, with the latter promoting the most precocious dormancy breaking registered in vitro.
Hence, the bioassay appears as a cost-effective tool that could be of interest for breeders, to characterize the chilling
requirements of flowers of parental plants or their offspring.
ornamental value.
Initiation and early differentiation of flower buds starts from late spring on while flower bud development and visible bud enlargement sequel until autumn.
In many temperate woody ornamentals, dormancy is installed after flower bud differentiation.
The exposure of floral buds to cold temperatures (between 2-7°C) will enhance dormancy release and initiate normal growth and anthesis during the next spring.
To quantify the cold requirement five low temperature regimes,
consisting of darkness and a constant temperature of 7°C applied for 0, 2, 4, 6 and
8 weeks, were tested on budded plants of the cultivar Nuccios Pearl. As indicator of dormancy release, an inexpensive and easygoing test was conducted by forcing
excised flower buds in an in vitro bioassay.
Simultaneously a possible hormonal basis for this endodormancy was assessed by measuring the concentration of abscisic acid in floral buds.
Our results indicated that the bioassay is a suitable indicator of the moment of dormancy release as it was able to highlight a reduced amount of
dormancy when buds stayed longer at cold.
Abscisic acid content in floral buds
decreased after 6 and 8 weeks of cold, with the latter promoting the most precocious dormancy breaking registered in vitro.
Hence, the bioassay appears as a cost-effective tool that could be of interest for breeders, to characterize the chilling
requirements of flowers of parental plants or their offspring.
Authors
A. Berruti, A. Christiaens, M.C. Van Labeke, V. Scariot
Keywords
C. japonica, abscisic acid, cold treatment, chilling requirement
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