STUDIES ON THE LEGUME ROOT NODULE BACTERIA: I. DETECTION OF EFFECTIVE AND INEFFECTIVE STRAINS

Abstract

The Virtanen technique was used to detect effective and ineffective rhizobia. The rhizobia studied varied widely in their action towards different varieties of the same host species. Maximum leghemoglobin concentrations occurred just prior to blossoming in field legumes, but much earlier in greenhouse legumes cultivated under conditions of this experiment. The nodules of the ineffective strains of legume bacteria differed from those produced by effective strains in color, size, distribution, rate of destruction of the bacteroid area, and presence or absence of rodlike bacterial forms. Experimental evidence is presented to show that a supposedly parasitic strain of alfalfa organism can exist.