Data/hora: 26/06/2024 15:42:24

Biblioteca(s): | Epagri-Sede.
Data corrente: | 10/04/2015
Data da última atualização: | 10/04/2015
Autoria: | SCHMITZ, J. D.; BONHOMME, M.; COCHARD, H.; HERTER, F. G.; LEITE, G. B.; REGNARD, J.; LAURI, P.
Título: | Are the effects of winter temperatures onspring budburst mediated by the bud water status or related to a whole-shoot effect? Insights in the apple tree.
Ano de publicação: | 2014
Fonte/Imprenta: | Trees, Berlim, 2014.
Idioma: | Português

Conteúdo:

The effects of winter temperatures, i.e., during
dormancy, on shoot architecture are well known with budburst
preferentially in the distal or the proximal part of the
parent shoot in cold and mild winter conditions, respectively.
However, the link with the overwintering bud water status is
still scarcely documented. Our study was developed on four
apple (Malus domestica Borkh.) cultivars covering a range of
chilling requirements from low (?Condessa?) to medium
(?Granny Smith?) and high (?Royal Gala?, ?Starkrimson?),
and maintained in either cold (1,428 h below 7.2 C) or mild
(99 h below 7.2 C) fluctuating winter temperatures. Our aim
was to analyze xylem conductance at the stem-to-bud junction,
and relative water content and water potential of the bud
itself, for buds situated in the distal third of one-year-old
shoots. From dormancy to the pre-budburst stage, xylem
conductance at the stem-to-bud junction increased or
decreased or did not show consistent changes depending on
the cultivar and the winter temperature treatment. Whatever
the cultivar, there were no significant trends across dates for
the effects of winter temperatures on bud water potential and
relative water content. Water potential had negative values,
between -4.35 and -2.24 MPa, across cultivars and winter
temperature treatments without a consistent relationship with
actual spring budburst frequency. These results suggested
that lateral buds were hydraulically isolated from the parent
stem during winter until a few days before budburst. We
discussed that the temperature-related spring budburst was
likely more related to a whole-shoot effect mediated by
hormonal, hydraulics and/or sugar signaling, than to the
individual bud water status during dormancy.

Palavras-Chave: | Apple; Axillary budburst; Relative water content; Water potential; Winter temperatures; Xylemhydraulic conductance.
Categoria do assunto: | F Plantas e Produtos de Origem Vegetal
URL: | http://intranetdoc.epagri.sc.gov.br/producao_tecnico_cientifica/DOC_35474.pdf
Registro original: | Epagri-Sede (Epagri-Sede)
Exemplares: | Epagri-Sede - (98653-1) - UPC - AP - DD -  -  -  - DIS