Clovers
Mostrando 1-11 de 11 artigos, teses e dissertações.
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1. Rendimento de grãos e características agronômicas de soja em função de pastagens perenes em sistema de plantio direto
O objetivo do presente estudo foi avaliar o desempenho de soja em sistemas de produção com integração lavoura-pecuária em plantio direto. Constituíram os tratamentos cinco sistemas de produção: sistema I (trigo/soja, ervilhaca/milho e aveia branca/soja); sistema II (trigo/soja, pastagem de aveia preta + ervilhaca/milho e aveia branca/soja); sistema I
Bragantia. Publicado em: 08/08/2014
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2. Rhizobium leguminosarum exopolysaccharide mutants: biochemical and genetic analyses and symbiotic behavior on three hosts.
Ten independently generated mutants of Rhizobium leguminosarum biovar phaseoli CFN42 isolated after Tn5 mutagenesis formed nonmucoid colonies on all agar media tested and lacked detectable production of the normal acidic exopolysaccharide in liquid culture. The mutants were classified into three groups. Three mutants harbored Tn5 insertions on a 3.6-kilobase
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3. Influence of Azospirillum Strains on the Nodulation of Clovers by Rhizobium Strains
Mixed cultures of several Azospirillum and Rhizobium trifolii strains caused either an inhibition or stimulation of nodule formation on plant hosts as compared with nodulation of plants inoculated with R. trifolii alone. Azospirillum strains affected the nodulation process at a precise cell ratio (R. trifolii/Azospirillum cells) and time of inoculation. All
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4. Plasmids and stability of symbiotic properties of Rhizobium trifolii.
A conjugal plasmid which encodes both peak nodulation genes and nitrogenase genes, and which is labeled with the transposon Tn5, was transferred to a wild-type Rhizobium trifolii strain to examine the stability and expression of the host range and fixation (Fix+) phenotypes. Transconjugates were isolated which were shown to initially form nitrogen-fixing nod
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5. DNA sequence of Rhizobium trifolii nodulation genes reveals a reiterated and potentially regulatory sequence preceding nodABC and nodFE.
The Rhizobium trifolii nod genes required for host-specific nodulation of clovers are located on 14 kb of Sym (symbiotic) plasmid DNA. Analysis of the nucleotide sequence of a 3.7 kb portion of this region has revealed open reading frames corresponding to the nodABCDEF genes. A DNA sequencing technique, using primer extension from within Tn5, has been used t
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6. Expression of Rhizobial Nitrogenase: Influence of Plant Cell-Conditioned Medium †
Conditioned medium was obtained from suspension cultures of soybean (Glycine max L. Merrit) cells after incubating them for 4 to 8 days with rhizobia which were separated from the soybean cells by two dialysis bags, one within another. This conditioned medium from the plant cell side (PCM) of the two membranes was used to elicit and influence nitrogenase act
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7. Sym plasmid transfer to various symbiotic mutants of Rhizobium trifolii, R. leguminosarum, and R. meliloti.
Two self-transmissible Sym(biosis) plasmids, one encoding pea-specific nodulation and nitrogen-fixation functions (plasmid pJB5JI) and the other encoding clover-specific nodulation and nitrogen-fixation functions (plasmid pBR1AN) were used to determine whether the symbiotic genes encoded on these plasmids are expressed in various members of the Rhizobiaceae.
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8. Evidence for Genetic Exchange and Recombination of Rhizobium Symbiotic Plasmids in a Soil Population
A soil population of 16 Rhizobium leguminosarum bv. trifolii isolates was characterized by using three Sym (for symbiotic) plasmid-specific DNA hybridization probes: (i) an R. leguminosarum bv. trifolii-specific, repeated-sequence probe; (ii) a nifHDK gene probe, and (iii) a nod gene probe. A predominant Sym plasmid family was identified among the isolates.
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9. Clovers secrete specific phenolic compounds which either stimulate or repress nod gene expression in Rhizobium trifolii
Rhizobium trifolii mutants containing Escherichia coli lac gene fusions to specific nodulation (nod) genes were used to characterise phenolic compounds secreted from the roots of white clover (Trifolium repens) plants. These compounds either had stimulatory or inhibitory effects upon the induction of the nod genes. The stimulatory compounds were hydroxylated
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10. Autecology in Rhizospheres and Nodulating Behavior of Indigenous Rhizobium trifolii†
Indigenous serotype 1-01 of Rhizobium trifolii occupied significantly fewer nodules (6%) on plants of soil-grown noninoculated subterranean clover (Trifolium subterraneum L.) cv. Woogenellup than on cv. Mt. Barker (36%) sampled at the flowering stage of growth. Occupancy by indigenous serotype 2-01, was not significantly different on the two cultivars (16 an
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11. The Flavin Content of Clovers Relative to Symbiosis with a Riboflavin-requiring Mutant of Rhizobium trifoli1
A riboflavin-requiring auxotroph of Rhizobium trifolii (T1/D-hisr-15) formed ineffective root nodules on red clover and on two cultivars of subterranean clover, but produced almost fully effective nodules on several other cultivars of subterranean clover. Fluorescence and bioassay measurements of the flavin content of the roots and shoots of these cultivars