Articles
Effect of abscisic acid and paclobutrazol on cold hardiness of rabbiteye blueberry (Vaccinium ashei Reade)
Article number
1117_51
Pages
315 – 320
Language
English
Abstract
Blueberries belong to the family Ericaceae and the genus Vaccinium which contains about 400 species of shrubs, woody vines and small trees.
A detailed study was conducted on rabbiteye blueberry cultivar ‘Tifblue’ in the spring season to determine the effect of three concentrations of abscisic acid (ABA) (0, 20, 40, and 60 mg L-1) and three concentrations of paclobutrazol (0, 100, 200, and 300 mg L-1) on cold hardiness of floral parts.
Two types of flower flushes were identified in ‘Tifblue’. Critical freezing temperatures and the effectiveness of the treatments were determined by conducting differential thermal analysis (DTA), electrolyte leakage, oxidative browning and tetrazolium staining.
Floral parts frozen to -40°C produced only one exotherm confirming that rabbiteye blueberries do not supercool.
DTA results indicated that the induction of cold hardiness by ABA and paclobutrazol was concentration dependent, but this phenomenon was not noticed in viability tests.
Results indicated that ABA and paclobutrazol induced hardiness only in certain parts of the first flush, but paclobutrazol with high concentrations induced more hardiness in all floral parts of the second flush.
Ovaries were the hardiest followed by calyx, stamens, style and stigma, and corolla.
Control treatments showed that floral parts at stage six developed in April were more prone to freezing injury compared to floral parts at stage six developed in March.
The data indicated that the air temperature had profound influence in cold hardiness, and the sequence of exotherms of DTA and LT50 of viability dependent on it.
A detailed study was conducted on rabbiteye blueberry cultivar ‘Tifblue’ in the spring season to determine the effect of three concentrations of abscisic acid (ABA) (0, 20, 40, and 60 mg L-1) and three concentrations of paclobutrazol (0, 100, 200, and 300 mg L-1) on cold hardiness of floral parts.
Two types of flower flushes were identified in ‘Tifblue’. Critical freezing temperatures and the effectiveness of the treatments were determined by conducting differential thermal analysis (DTA), electrolyte leakage, oxidative browning and tetrazolium staining.
Floral parts frozen to -40°C produced only one exotherm confirming that rabbiteye blueberries do not supercool.
DTA results indicated that the induction of cold hardiness by ABA and paclobutrazol was concentration dependent, but this phenomenon was not noticed in viability tests.
Results indicated that ABA and paclobutrazol induced hardiness only in certain parts of the first flush, but paclobutrazol with high concentrations induced more hardiness in all floral parts of the second flush.
Ovaries were the hardiest followed by calyx, stamens, style and stigma, and corolla.
Control treatments showed that floral parts at stage six developed in April were more prone to freezing injury compared to floral parts at stage six developed in March.
The data indicated that the air temperature had profound influence in cold hardiness, and the sequence of exotherms of DTA and LT50 of viability dependent on it.
Authors
G.K. Panicker, F.B. Matta
Keywords
differential thermal analysis, LT50, electrolyte leakage, tetrazolium staining, oxidative browning, exotherms
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