02289nam a2200265 a 450000100080000000500110000800800410001910000180006024500950007826000750017350000270024852015430027565000120181865000170183065000110184765000120185865000160187065000230188665000090190965300080191865300080192665300400193465300290197465300200200316217172012-09-19       1981    bl uuuu  m   00u1 u    #d1 aFRANCO, A. A.  aAcidity factors limiting nodulation, nitrogen fixation und growth of Phaseolus vulgaris L.  a1981. 144 p. Tese (Doutorado) - University of California, Davis.c1981  aOrientada: D.N. Munns.  aBean (Phaseolus vulgaris L.) is extensively grown in tropical regions, mostly in developing countries without use of N-fertilizer. However, root nodulation and N2-fixation has been found variable under acidic conditions, when soil is used as growth medium. Conditions and techniques for achieving good nodulation of bean in continuous aerated solution culture were developed. The effects of pH on uptake and distribution of Mo in bean were studied in greenhouse and growth chamber experiments in soil and solution culture. The effects of pH and Al on nodule initiation and growth, nitrogen fixation (C2H2-reduction) and shoot and root growth were studied in solution and san culture. Growth and nitrogenase activity of nodule and plant growth in solution culture were atleast as good as in gravel. However, nodule initiation was restricted to plants inoculated before or imediately after transfer of seedlings to solution and was restricted to the roots already present before transfer. Lack of nodulation could not be explained by failure of bacteria to colonize the root or absence of root hairs. There were indications that the P-status of the plant together with a factor or factors that had to accumulate or deplete in solution, determined success or failure of nodulation. Daily application of 0.5-1.0 mg N per plant delayed nodule growth and nitrogen fixation slightly, but increased plant growth and alleviated the severe N-deficiency stress before the onset of N2-fixation. In six cultivars, Mo uptake in solution culture was ...  aacidity  akidney beans  aAcidez  aFeijão  aNodulação  aPhaseolus Vulgaris  aRaiz  aBNF  aFBN  aFixação biológica de nitrogênio  aNitrogen fixing bacteria  aRoot nodulation