Data/hora: 09/06/2024 18:11:24

Biblioteca(s): 	Embrapa Semiárido.	
Data corrente: 	29/01/2018	
Data da última atualização: 	06/08/2019	
Autoria: 	FREITAS, S. T. de; AMARANTE, C. V. T. do; DANDEKAR, A. M.; MITCHAM, E. J.	
Afiliação: 	SERGIO TONETTO DE FREITAS, CPATSA; CASSANDRO VIDAL TALAMINI DO AMARANTE, UFSC; A.M. Dandekar, Department of Plant Sciences, University of California, Davis, CA 95616, USA.; E.J. Mitcham, Department of Plant Sciences, University of California, Davis, CA 95616, USA.	
Título: 	Mechanisms regulating bitter pit development in Greensleeves apples with suppression of ethylene biosynthesis.	
Ano de publicação: 	2017	
Fonte/Imprenta: 	Acta Horticulturae, Leuven, n. 1179, p. 61-68, nov. 2017.	
ISSN: 	978-94-62611-75-7	
DOI: 	10.17660/ActaHortic.2017.1179.10	
Idioma: 	Português	
Conteúdo: 	Bitter pit (BP) is a physiological disorder in apple believed to be triggered by low fruit Ca2+ content and enhanced by ethylene. The objectives of this study were to understand the role of ethylene, Ca2+ binding to the cell wall and the ratio between Ca2+ and other nutrients (Mg2+, K+ and N) on BP development in wild-type (GS) and ethylene-suppressed (68G and 103Y) ?Greensleeves? apples. The transgenic line 68G is suppressed for 1-aminocyclopropane-1-carboxylic acid (ACC) oxidase (ACO), and line 103Y is suppressed for ACC synthase (ACS). Suppression of ethylene biosynthesis reduced the incidence and severity of BP, and decreased the rate of fruit softening and the degree of cell-wall pectin de-esterification in fruit cortical tissue. Lower ethylene biosynthesis, in ethylene-suppressed genotypes, had no effect on Ca2+, Mg2+, K+ or N concentrations in cortical tissue, on Ca2+ concentrations in the cell wall, on expression of pectin methylesterases (PME1 and PME2) or on percentages of cortical Ca2+ bound to the cell wall. In all genotypes, fruit with BP had lower Ca2+ and higher Mg2+ concentrations and higher Mg2+/Ca2+ ratios in cortical tissue, as well as higher percentages of cortical Ca2+ bound to the cell wall, compared with fruit without BP. Fruit with and without BP had similar cell-wall Ca2+ concentrations, and cell-wall content and levels of PME expression in cortical tissue. The results indicate that high levels of ethylene biosynthesis, Ca2+ binding to the cell wall and Mg2+ in cortical tissue can enhance fruit susceptibility to BP.	
Palavras-Chave: 	Deficiencia de cálcio; Desordem fisiológica.	
Thesagro: 	Cálcio; Fisiologia Nutricional; Maça; Malus Domestica; Pós-Colheita.	
Thesaurus Nal: 	Ethylene; Genetic disorders; Physiological response; Postharvest treatment.	
Categoria do assunto: 	G Melhoramento Genético	
Registro original: 	Embrapa Semiárido (CPATSA)	
Exemplares: 	CPATSA - (57132-1) - UPC - AP - DD -  -  -  - DIS