Advanced search
1 file | 192.05 KB

Flowering response of an early and late flowering azalea cultivar (Rhododendron simsii) to cold treatment

Author
Organization
Abstract
Azalea flower bud differentiation is followed by a period of dormancy which is broken by cold. In this research two cultivars with different cold requirements (the early flowering cultivar 'Nordlicht' and the late flowering cultivar 'Mw. G. Kint') were kept at 7 degrees C after flower bud differentiation and monitored weekly. To follow dormancy release, endogenous abscisic acid (ABA) concentrations in the flower buds were measured and opening of buds was assessed by an in vitro bio-assay, testing the sensitivity to exogenous ABA. Flower buds of 'Nordlicht' had a steady ABA content for 5 weeks at 7 degrees C, indicating that endogenous ABA concentrations are not directly linked to dormancy breaking. The in vitro bio-assay on the other hand showed that four weeks of 7 degrees C are required for 'Nordlicht' to lose sensitivity to exogenous ABA. For 'Mw. G. Kint' there was a decrease in ABA content until 7 weeks at 7 degrees C, and flower buds lost sensitivity to exogenous ABA after 7 weeks. Carbohydrate and starch content in leaves and buds were examined since these are important in the successive forcing period. Starch levels in the leaves decreased with increasing cold period. 'Nordlicht' flower buds responded to the cold treatment by biosynthesis of raffinose and stachyose, flower buds of 'Mw. G. Kint' maintained the initial concentration of those carbohydrates. Finally the actual flowering response was monitored by forcing weekly 10 plants from 7 degrees C in the greenhouse. The results showed that at least 4 weeks are required to break dormancy for 'Nordlicht' confirming the results of the in vitro opening of the buds, while at least 6 weeks are required for 'Mw. G. Kint'.
Keywords
bio-assay, Rhododendron, flowering, carbohydrates, abscisic acid, dormancy, GIBBERELLIC ACID

Downloads

  • (...).pdf
    • full text
    • |
    • UGent only
    • |
    • PDF
    • |
    • 192.05 KB

Citation

Please use this url to cite or link to this publication:

Chicago
Christiaens, Annelies, Marie-Christine Van Labeke, Els Pauwels, Bruno Gobin, Ellen De Keyser, and Jan De Riek. 2013. “Flowering Response of an Early and Late Flowering Azalea Cultivar (Rhododendron Simsii) to Cold Treatment.” In Acta Horticulturae, ed. Johan Van Huylenbroek, Marie-Christine Van Labeke, and Katrijn Van Laere, 990:83–89. Leuven, Belgium: International Society for Horticultural Science (ISHS).
APA
Christiaens, A., Van Labeke, M.-C., Pauwels, E., Gobin, B., De Keyser, E., & De Riek, J. (2013). Flowering response of an early and late flowering azalea cultivar (Rhododendron simsii) to cold treatment. In J. Van Huylenbroek, M.-C. Van Labeke, & K. Van Laere (Eds.), Acta Horticulturae (Vol. 990, pp. 83–89). Presented at the 2nd International symposium on Woody Ornamentals of the Temperate Zone, Leuven, Belgium: International Society for Horticultural Science (ISHS).
Vancouver
1.
Christiaens A, Van Labeke M-C, Pauwels E, Gobin B, De Keyser E, De Riek J. Flowering response of an early and late flowering azalea cultivar (Rhododendron simsii) to cold treatment. In: Van Huylenbroek J, Van Labeke M-C, Van Laere K, editors. Acta Horticulturae. Leuven, Belgium: International Society for Horticultural Science (ISHS); 2013. p. 83–9.
MLA
Christiaens, Annelies, Marie-Christine Van Labeke, Els Pauwels, et al. “Flowering Response of an Early and Late Flowering Azalea Cultivar (Rhododendron Simsii) to Cold Treatment.” Acta Horticulturae. Ed. Johan Van Huylenbroek, Marie-Christine Van Labeke, & Katrijn Van Laere. Vol. 990. Leuven, Belgium: International Society for Horticultural Science (ISHS), 2013. 83–89. Print.
@inproceedings{4185060,
  abstract     = {Azalea flower bud differentiation is followed by a period of dormancy which is broken by cold. In this research two cultivars with different cold requirements (the early flowering cultivar 'Nordlicht' and the late flowering cultivar 'Mw. G. Kint') were kept at 7 degrees C after flower bud differentiation and monitored weekly. To follow dormancy release, endogenous abscisic acid (ABA) concentrations in the flower buds were measured and opening of buds was assessed by an in vitro bio-assay, testing the sensitivity to exogenous ABA. Flower buds of 'Nordlicht' had a steady ABA content for 5 weeks at 7 degrees C, indicating that endogenous ABA concentrations are not directly linked to dormancy breaking. The in vitro bio-assay on the other hand showed that four weeks of 7 degrees C are required for 'Nordlicht' to lose sensitivity to exogenous ABA. For 'Mw. G. Kint' there was a decrease in ABA content until 7 weeks at 7 degrees C, and flower buds lost sensitivity to exogenous ABA after 7 weeks. Carbohydrate and starch content in leaves and buds were examined since these are important in the successive forcing period. Starch levels in the leaves decreased with increasing cold period. 'Nordlicht' flower buds responded to the cold treatment by biosynthesis of raffinose and stachyose, flower buds of 'Mw. G. Kint' maintained the initial concentration of those carbohydrates. Finally the actual flowering response was monitored by forcing weekly 10 plants from 7 degrees C in the greenhouse. The results showed that at least 4 weeks are required to break dormancy for 'Nordlicht' confirming the results of the in vitro opening of the buds, while at least 6 weeks are required for 'Mw. G. Kint'.},
  author       = {Christiaens, Annelies and Van Labeke, Marie-Christine and Pauwels, Els and Gobin, Bruno and De Keyser, Ellen and De Riek, Jan},
  booktitle    = {Acta Horticulturae},
  editor       = {Van Huylenbroek, Johan and Van Labeke, Marie-Christine and Van Laere, Katrijn},
  isbn         = {9789066054776},
  issn         = {0567-7572},
  keywords     = {bio-assay,Rhododendron,flowering,carbohydrates,abscisic acid,dormancy,GIBBERELLIC ACID},
  language     = {eng},
  location     = {Ghent, Belgium},
  pages        = {83--89},
  publisher    = {International Society for Horticultural Science (ISHS)},
  title        = {Flowering response of an early and late flowering azalea cultivar (Rhododendron simsii) to cold treatment},
  url          = {http://www.actahort.org/books/990/990_7.htm},
  volume       = {990},
  year         = {2013},
}

Web of Science
Times cited: