Learn More
N2 fixation in lines of Phaseolus vulgaris was measured by 15N-isotope dilution to determine whether a programme of crossing and recurrent selection had resulted in enhanced nitrogen fixation. In field experiments on an isohyperthermic Aquic Hapludoll soil the amount of N2 fixed by the different lines ranged from 18 to 36 kg ha−1 (32 to 47% of plant N) in(More)
Field experiments were performed in Austria, Brazil, Chile, Colombia, Guatemala, Mexico and Peru as part of an FAO/IAEA Co-ordinated Research Programme to investigate the nitrogen fixing potential of cultivars and breeding lines of common bean (Phaseolus vulgaris L.). Each experiment included approximately 20 bean genotypes which were compared using the 15N(More)
Nitrogen fixation in nine common bean (Phaseolus vulgaris L.) lines was estimated using the 15N isotope dilution method at two locations in two seasons. In the first season at one location no N2 fixation was detected while in the second season up to 51 kg N ha−1 were estimated. There were significant differences between lines and correlations between trials(More)
Six Rhizobium leguminosarum bv. phaseoli strains (Ciat 151, Ciat 895, Ciat 899, CE3, H2C, Kim5s) were tested for nodule occupancy in different bean cultivars at two field sites (one fertile, one acid tropical soil) and in the greenhouse. The effects of several environmental factors such as low pH, high temperature, Al and Mn toxicity, iron deficiency, bean(More)
delta-Aminolevulinic acid accumulated in the culture medium when Agmenellum quadruplicatum strain PR-6 was incubated in the presence of levulinic acid, a competitive inhibitor of delta-aminolevulinic acid dehydratase, and specifically labeled glutamate and glycine. The delta-aminolevulinic acid was purified using Dowex 50W-X8 and cleaved by periodate to(More)
When levulinic acid was added to a growing culture of the cyanobacterium (blue-green alga) Agmenellum quadruplicatum PR-6, delta-aminoelevulinic acid accumulated in the medium and chlorophyll a synthesis and cell growth were inhibited, but there was a small amount of c-phycocyanin synthesis. The amount of delta-aminolevulinic acid produced in the treated(More)
A spontaneous, stable, pigmentation mutant of Nostoc sp. strain MAC was isolated. Under various growth conditions, this mutant, R-MAC, had similar phycoerythrin contents (relative to allophycocyanin) but significantly lower phycocyanin contents (relative to allophycocyanin) than the parent strain. In saturating white light, the mutant grew more slowly than(More)
Plant genotypes that limit nodulation by indigenous rhizobia while nodulating normally with inoculant-strain nodule occupancy in Phaseolus vulgaris. In this study, eight of nine Rhizobium tropici strains and six of 15 Rhizobium etli strains examined, showed limited ability to nodulate and fix nitrogen with the two wild P. vulgaris genotypes G21117 and(More)
  • 1