Data/hora: 29/06/2024 09:04:49

Biblioteca(s): 	Epagri-Sede.	
Data corrente: 	14/04/2011	
Data da última atualização: 	14/04/2011	
Autoria: 	LEITE, G. B.; BONHOMME, M.; LACOINTE, A.; RAGEAU, R.; SAKR, S.; GUILLIOT, A.; MAUREL, K.; PETEL, G.; RODRIGUES, A. C.	
Afiliação: 	Epagri	
Título: 	Influence of Lack of Chilling on Bud-break Patterns and Evolution of Sugar Contents in Buds and Stem Tissues along the One-year-old Shoot of the Peach Trees.	
Ano de publicação: 	2004	
Fonte/Imprenta: 	Acta Horticulturae, Brugge, v. 662, n. , p. 61-71, 2004.	
Idioma: 	Inglês	
Notas: 	ISSN, 0567-7572	
Conteúdo: 	Through experiments providing different amounts of chilling to trees before
they were given forcing temperatures, the influence of this amount on the budbreak
pattern of peach tree was investigated with special regards to the dynamics of
development of the buds according to their place along the twig. Vegetative and
floral budbreak was recorded on the trees. Leaf bud endodormancy was
characterized by the mean time of bud break (MTB) through the ?cuttings? test. Dry
weight of floral primordia was measured. On the basis of the hypothesized ?trophic?
control of the primordia growth and development, sucrose, sorbitol, fructose and
glucose contents were assayed in the buds and stem. Under natural conditions (NC) and under total chilling deprivation (TCD) the results on bud development (MTB, growth of floral primordia) and budbreak (good budbreak under NC, no budbreak under TCD) confirmed former results on peach (especially, under both treatments no gradients along the twig). Under NC, in floral buds, the sugar contents showed at the budbreak time starch and hexose increases and a decrease of sucrose and sorbitol. In leaf buds, only the starch showed an increase. Sucrose, sorbitol and hexoses stayed stable. Under TCD, all carbohydrates stayed stable.
Under the treatment ?chilling amount = 1/3 requirements? (PCD1), a few
buds broke. The rates of leaf and floral budbreaking (consistently with MTB data)
and floral bud drop showed longitudinal gradients. The dynamics of sugar specific
contents showed a transitory oscillation, in opposite way in leaf and floral buds, and
with stronger amplitude at the basal part of the stem. In floral buds, the sugar
contents at the budbreak time stayed stable to starch and hexose, decreased for
sorbitol and increase for hexoses. In leaf buds, all carbohydrates stayed stable.
Under the treatment ?chilling amount = 2/3 requirements? (PCD2), most leaf
and many floral buds broke, but many flowers dropped at bloom. Slight acrotonic
gradients could be observed. For most of the sugars and tissues the dynamics of
sugar specific contents looked like those under NC; however, they showed gradients
(for instance, an early hexoses gradient consistent with the acrotonic floral buds
bloom). In floral buds, the sugar contents showed at the budbreak time a starch and
sucrose stability, a decrease of sorbitol and an increase of hexoses. In leaf buds, only
the starch increased. Sucrose, sorbitol and hexoses stayed stable.
The availability of carbohydrates would not be the key factor of the pattern
of budbreak. The capacity to use soluble sugars seems to be more critical. The capacity to synthesize starch could be a marker for growth capacity.
	
Palavras-Chave: 	Bud position; Carbohydrate gradients; Dormancy; Prunus persica.	
Categoria do assunto: 	--	
URL: 	http://intranetdoc.epagri.sc.gov.br/producao_tecnico_cientifica/DOC_1198.pdf	
Registro original: 	Epagri-Sede (Epagri-Sede)	
Exemplares: 	Epagri-Sede - (78384-1) - UPC - AP - -- -  -  -  - DIS