01992naa a2200157 a 450000100080000000500110000800800410001910000190006024500860007926000090016552015220017465000260169670000190172270000130174177300800175414770382018-07-13       1976    bl uuuu     u00u1 u    #d1 aDOBEREINER, J.  aEcological distribution of Spirillum lipoferum Beijerinck.h[electronic resource]  c1976  aA survey in various countries revealed that the N2-fixing Spirillum lipoferum Beijerinck is a very common root and soil inhabitant in the tropics. More than half of the grass root and soil samples collected in tropical countries (four African countries and Brazil) contained abundant S.lipoferum populations, while less tahn 10% of the sample collected in tempearte South Brazil, Kenya, and the U.S.A. Contained the organism. There is a pronounced vegetation effect. Panicum maximum seems the most favorable among the forage grasses, while few positive samples were found under virgin tropical forest. Legume roots contained less S. lipoferum thanadjancent soils. More than 80% of the samples from cereal roots (maize, sorghum, wheat, and rye) grown in fields fertilized with PK and Mo, in Rio de Janeiro State, were positive. maize and sorghum grown under similar conditions in Wisconsin contained less than 10% of positive samples, but when maize fields were inoculated 90% of the root samples contained S. lipoferum. Alluvial soils were more favorable than eroded hill soils. Occurrence in soil was strongly pH-dependent with a pH around 7, being optimal (correlation coefficient r = 0,90). Sporadic occurrence was observed even in soils with pH 4.8. surface-sterilized P. maximum roots collected from soils with pH ranging from 4.8 to 7.2 contained high S. lipoferum numbers which did not correlate with soil pH (r =0,41). Amendment with malate of acid soils was not very effective in increasing nitrogenase (...)  aMicrobiologia do solo1 aMARRIEL, I. E.1 aNERY, M.  tCanadian Journal of Microbiology, Ottawagv. 22, n. 10, p. 1464-1473, 1976.