Relationships Amongst the Fast‐growing Rhizobia ofLablab purpureus, Leucaena leucocephala, Mimosaspp.,Acacia farnesianaandSesbania grandifloraand their Affinities with Other Rhizobial Groups

摘要

Colony characteristics, growth in litmus milk, precipitation in calcium glycerophosphate medium and utilization of carbon sources of the root‐nodule bacteria isolated from the tropical legumesLeucaena, Mimosa, Acacia, SesbaniaandLablabwere similar to fast‐growing rhizobia of temperate legumes, particularlyRhizobium meliloti.In agglutination tests, isolates from each host shared antigens with one or more of fiveRhizobiumstrains fromLeucaena.Infective characteristics of the fast‐growing rhizobia were studied in modified Leonard jars and in agar culture. Cross‐infections by rhizobia between these plants were common and the association often effective.Lablabwas effectively nodulated by its own fast‐growing isolate but only formed root swellings, possibly ineffective pseudonodules, with the other isolates. Slow‐growing rhizobia which were able to nodulateMacroptilium atropurpureuswere unable to form nodules on these legumes exceptLablabwhich was considered more akin to the cowpea group. All fast‐growing isolates nodulated, often effectively,Vigna unguiculataandV. unguiculatassp.sesquipedalis.The isolate fromLablabalso effectively nodulated a number of other tropical legumes which have previously only been reported to nodulate with slow‐growing nodule bacteria and it also produced ineffective nodulation onMedicago sativa.This is the first record of an effective fast‐growing i