The effect of N, Ni, Mo, Co and S omission on the N and S leaf contents of common bean plants (Phaseolus vulgaris), grown in a greenhouse, was evaluated. The experimental design was factorial, using two soil types (Entisol and Cambisol), two inoculation levels (with and without Rhizobium), combined with six fertilization treatments: (a) Complete (N, P, K, Ni, Mo, Co and S); (b) without N; (c) without Ni; (d) without Co; (e) without Mo; (f) without S. The experimental […]

Seeds of common bean (Phaseolus vulgaris L.) with high P concentration, obtained from plants which had received foliar fertilization, were used in a greenhouse experiment to evaluate the effects of seed P concentration on growth and nodulation of common bean during the vegetative stage.The experiment had a 2x2x 3×3 factorial randomized block design with four replicates: two cultivars (Carioca and Rio Tibagi), two seed P concentrations (low and high, corresponding to 4.3 and 5.6mgg-1 for Carioca, and 4.8 and 6.3mgg-1 […]

The effectiveness of the nitrogen supplying to bean plants as fertilizer and, or, as biological nitrogen fixation, and the dependence of these processes on molibdenum availability is still a not well solved problem. The objective of this study was to evaluate the effect of foliar application of Mo on nitrogenase and nitrate reductase activities and on productivity of beans cultivated on a Red Yellow Podzolic, in Coimbra, MG (Brazil). The treatments consisted of increasing rates of foliar application of Mo […]

The first steps of molecular signal exchange between the bean plant and its Rhizobium spp. microsymbionts were studied. The effects on nodulation of the addition of seed exudates of two different leguminous tree plants, Mimosa flocculosa or Leucaena leucocephala, in the presence of R. tropici, R. etli or R. leguminosarum bv. phaseoli were studied. The expression of nod genes was also measured “in vitro” by the activity of ß-glucuronidase on different genetically modified strains possessing the fusion nodA::gusA, using as […]

Three series of experiments were carried out. In the first, the effects of N, Mo, and rhizobium were studied at two municipalities; in the second, conducted at another municipality, a factorial with four rates of N (0, 30, 60, and 90 kg ha-1) and four rates of Mo (0, 40, 80, and 120 g ha-1) was studied; and in the third, at six municipalities, the following combinations of N at planting time (kg ha-1), N as side dressing (kg ha-1) […]