Data/hora: 25/06/2024 18:35:22

Biblioteca(s): | Embrapa Agrobiologia.
Data corrente: | 09/08/2004
Data da última atualização: | 09/08/2004
Autoria: | OKITO, A.; ALVES, B. J. R.; URQUIAGA, S.; BODDEY, R. M.
Título: | Isotopic fractionation during N2 fixation by four tropical legumes.
Ano de publicação: | 2004
Fonte/Imprenta: | Soil Biology & Biochemistry, Oxford, v. 36, p. 1179-1190, 2004.
Idioma: | Inglês
Conteúdo: | To quantify the contribution of biological nitrogen fixation (BNF) to legume crops using the 15N natural abundance, it is necessary to determine the 15N abundance of the N derived from BNF-the B value. In this study, we used a technique b where by both legume and non-N²-fixing reference plants were grown under the same conditions in two similar soil, one artificially labelled with 15N, and the other not. the proportion of n derived from BNF (% Ndfa) was determined from the plants grown in the 15N-labelled  soil and it was assumed that the %Ndfa values of the legumes grow in the soil were the same, hence the B value of the legume could be calculated. The legume used were velvet neam (Mucuna pruriens), sunnhemp (Crotalaria juncea), groundnut (Arachis hypogaea) and (glycine max) inoculated, or not, with different strains of rhizobium. The values of % Ndfa were allover 89%, and all the legume grown in unlabelled soil showed negative alpha 15N values even though the plant-available n in this soil was found approximately + 6.0%. The B values for the shoot tissue (Bs) were calculated and ranged from approximately - 1.4% for inoculated sunnhemp and groudnut to - 2.4 and - 4.5% for soybeam inoculated with bradyhizobium japonicum strain CPAC 7 bradyhizobium alkanil 29W, rspectively. The B (Bwp) values for the whole plants roots, nodules and the original seed n were still significantly different detween the soybeam plants inoculated with CPAC 7 (- 1.33%) and 29W (- 2.25%). In a parallet experiment conducted in monoxenic culture using the soybeam variety and Bradyhizobium strain, the plants accumulated less N from BNF and the values were less negative, but still significantly different for soybean inoculated with the two different Bradyhizobium strains. The results suggest that the technique utilized in this study ti determine B with legume plants grown in soil in the poen air, yields B values that are more appropriate for use under field conditions.
Palavras-Chave: | Biological nitrogen fixation; BNF; FBN; Fixação biológica de nitrogênio; Groundnut.
Thesagro: | Amendoim; Arachis Hypogaea; Crotalária Juncea; Glycine Max; Soja.
Thesaurus Nal: | Mucuna pruriens; soybeans.
Categoria do assunto: | --
Registro original: | Embrapa Agrobiologia (CNPAB)
Exemplares: | CNPAB - (30449-1) - UMT - SP - -- -  -  - 0022756 - DIS