02633naa a2200313 a 450000100080000000500110000800800410001910000180006024500900007826000090016852017600017765000370193765000150197465000140198965000210200365000160202465300260204065300330206665300080209965300240210765300080213165300400213965300230217965300070220270000170220970000200222670000160224677300570226216247202003-10-23       2003    bl ---       0--  u    #d1 aBODDEY, R. M.  aEndophytic nitrogen fixation in sugarcanebPresent knowledge and future applications.  c2003  aIn Brazil the long-term continuous cultivation of sugarcane with low N fertilised inputs, without apparent depletion of soil-N reserves, led to the suggestion that N2-fixing bacteria associated with the plants may be the source of agronomically significant N inputs to this crop. From the 1950s to 1970s, considerable numbers of N2-fixing bacteria were found to be associated with the crop, but it was not until the late 1980s that evidence from N balance and ISN dilution experiments showed that some Brazilian varieties of sugarcane were able to obtain significant contributions from this source. The results of these studies renewed the efforts to search for N2-fixing bacteria, but this time the emphasis was on those diazotrophs that infected the interior of the plants. Within a few years several species of such .endophytic diazotrophs' were discovered including Gluconacetobacter diazotrophicus, Herbaspirillum .Seropedicae, H. rubrisubalbicans and Burkholderia sp. Work has continued on these endophytes within sugarcane plants, but to date little success has been attained in elucidating which endophyte is responsible for the observed BNF and in what site, or sites, within the cane plants the N2 fixation mainly occurs. Until such important question8 are answered further developments or extension of this novel N2-fixing system to other economically important non-legumes (e.g. cereals) will be seriously hindered. As far as application of present knowledge to maximise BNF with sugarcane is concerned, molybdenum is an essential micronutrient. An abundant water supply favours high BNF inputs, and the best medium term strategy to increase BNF would appear to be based on cultivar selection on irrigated N deficient soils fertilised with Mo.  aGluconacetobacter diazotrophicus  amolybdenum  asugarcane  aCana de Açúcar  aMolibdênio  aBactéria endofítica  aBiological nitrogen fixation  aBNF  aEndophytic bacteria  aFBN  aFixação biológica de nitrogênio  aHerbaspirillum spp  aMo1 aURQUIAGA, S.1 aALVES, B. J. R.1 aREIS, V. M.  tPlant and Soil, Dordrechtgv. 252, p. 139-149, 2003.