Data/hora: 06/06/2024 15:39:36

Biblioteca(s): 	Embrapa Agrobiologia.	
Data corrente: 	24/06/1997	
Data da última atualização: 	24/06/1997	
Autoria: 	CHRISTIANSEN-WENIGER, C.	
Título: 	Influence of Azospirillum spp. on the nitrogen supply of a gramineous host.	
Ano de publicação: 	1991	
Fonte/Imprenta: 	Wageningen: Landbouwuniversiteit, Out., 1991.	
Páginas: 	101p.	
Série: 	Tese de Doutorado.	
Idioma: 	Inglês	
Notas: 	Tese de Doutorado. Orientada por: A.J.Zehnder e J.A.van Veen.	
Conteúdo: 	The main objectives of this study were to identify factors that control the behaviour of Azospirillum in the rhizosphere gramineous plant in order to be able to optimize the association between the bacteria and the host plants in terms of nitrogen supply to the host. Plant produced growth substances such as the auxines indole-acetic-acid (IAA) and 2,4-dichlorphenoxy-acetic-acid (2,4 D) or gibberilic acid enhance the acetylene reduction activity of a pure A.brasiliense culture. IAA and the cytocinine 6-benzylaminopurine also stimulated bacterial growth. It should be pointed out, that Azospirillum also produces IAA itself, which is often mentioned to be the reason of its plant-growth stimulating activity. When associated with living roots, the nitrogen fixation(acetylene reduction) activity of Azospirillum brasiliense is much less sensitive to the repressive influence of free oxygen and mineral nitrogen, i.e. N03 and NH4+, than in the absent of an active growing root. Potencial acetylene reduction rates varied from 10 to 550 nmol C2H4 h-1 plant-1 depending on environmental conditions. In order to be able to determine the fate of introduced Azospirillum in a soil and in the root environment A.brasiliense strains were marked by a transposon (Tn5) insertion into genome so that reisolation upon double resistance against kanamycin and rifampicin was possible. A.brasiliense::Tn5 established in the rhizosphere of an axenically grown spring wheat to cell numbers as high as 10x10x10x10x10x10 cells per gram dry rhizosphere...	
Palavras-Chave: 	Al; Aluminium; Azospirillum brasiliense; BNF; Evironments; FBN; Fixacao biologica de nitrogenio; Nitrogen fixing bacteria; Plants; Reduction; Root; Sorghum.	
Thesagro: 	Acetileno; Alumínio; Bactéria; Genética; Gramínea; Gramineae; Meio Ambiente; Planta; Raiz; Redução; Rizosfera; Solo; Sorgo; Trigo.	
Thesaurus Nal: 	acetylene; genetics; rhizosphere; soil; wheat.	
Categoria do assunto: 	--	
Registro original: 	Embrapa Agrobiologia (CNPAB)	
Exemplares: 	CNPAB - (25356-1) - ADD - TS - -- - 633.2 - C555i - 1994.00006 - DIS