Data/hora: 11/06/2024 04:00:00

Provedor de dados: 	Brazilian Journal of Plant Physiology	
País: 	Brazil	
Título: 	Effects of light and ethylene on endogenous hormones and development of Catasetum fimbriatum (Orchidaceae)	
Autores: 	Suzuki,Rogério M.; Kerbauy,Gilberto B.	
Data: 	2006-09-01	
Ano: 	2006	
Palavras-chave: 	Auxin; Cytokinins; Etiolation; Plant growth; Plant hormones.	
Resumo: 	This study attempted to clarify the effects of dark, light and ethylene on plant growth and endogenous levels of indole-3-acetic acid (IAA), cytokinins and abscisic acid in Catasetum fimbriatum. Dark-incubation fully inhibited root and pseudobulb formation as well as leaf growth, but favored shoot elongation. The results of continuous and active growth in dark-incubated shoots (stolons) were induced by strong apical meristem sink activity and by the significantly increased levels of cytokinins in shoots. In fact, shoot length, cytokinin and IAA levels in dark-incubated shoots were about twice as great as for those grown under light conditions. Moreover, the total cytokinin level in shoots of C. fimbriatum under light conditions without ethylene was significantly higher than that found in roots. High levels of cytokinins in dark-grown stolons may be closely related to the absence of roots in C. fimbriatum. Under light conditions, the increased IAA level in shoots is mediated by ethylene. However, ethylene caused a significant increase of cytokinins in roots of light-treated plants, which may be involved in the retardation of root growth. Since the difference of cytokinins in shoots between ethylene-treated and non-treated plants under light conditions is small, it is concluded that the marked inhibition of leaf growth in ethylene-treated plants can be attributed to ethylene. Zeatin and zeatin riboside are the major cytokinins in C. fimbriatum regardless of the light conditions, ethylene treatment or organ types.	
Tipo: 	Info:eu-repo/semantics/article	
Idioma: 	Inglês	
Identificador: 	http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1677-04202006000300002	
Editor: 	Brazilian Journal of Plant Physiology	
Relação: 	10.1590/S1677-04202006000300002	
Formato: 	text/html	
Fonte: 	Brazilian Journal of Plant Physiology  v.18 n.3 2006	
Fonte: 	info:eu-repo/semantics/openAccess