ISSN:
1573-5036
Keywords:
Competition
;
Cowpea
;
Ineffective
;
Mutagenesis
;
Mutants
;
Nodulation
;
Rhizobium
;
Symbiotic and asymbiotic nitrogen-fixation
Source:
Springer Online Journal Archives 1860-2000
Topics:
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
Notes:
Summary A strain of cowpea Rhizobium was mutagenised and two ineffective mutants, M1 and M2, and an effective mutant, M3, were isolated. M1 produced more, but smaller nodules than the wild-type; these nodules lacked leghaemoglobin. M2 and the parental strain had similar nodulation characteristics, both forming large pink nodules. Plants inoculated with M3, nodulated earlier, produced more nodules (58%), had increased dry weights (26%) and the excised roots expressed greater acetylene (C2H2) reducing activity (39%) than plants inoculated with the wild-type. When competing with an indigenous population of effective rhizobia for nodule sites, M3 produced a higher proportion of the nodules (70–80%) than the parental strain (40–53%). M3 and the parental strain exhibited comparable rates of asymbiotic C2H2 reduction when grown on a defined medium, whereas M1 and M2 were inactive. The symbiotic properties of the mutants were unchanged after their reisolation following plant passage.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF02149631
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