Untersuchungen über die Leguminosen-Bakterien und -Pflanzen. X. Mitteilung (1). Über die Tätigkeit der Leguminosenbakterien und die Ausnutzung des in Wurzelknöllchen der Leguminosen gebundenen Stickstoffs durch Nicht-Leguminosen

Respiratory Enzyme Systems in Symbiotic Nitrogen Fixation I

“…The rate of growth decreased rapidly on either side of the optimum to the limits for growth of pH 4.5 and 9.5. The data of Virtanen and v. Hausen (1931) indicate that the pH optimum for growth of R. trifolii on nutrient gelatin extends from 6.5 to 7.5 and that the optimum for fixation of atmospheric nitrogen by modulated red clover plants is from 6.5 to 7.0 with limits at pH 4.0 and 8.5. Apparently, the optimum reaction for respiration by resting cells of R. trifolii is somewhat more acid than the previously observed values for growth of the various Rhizobium species.…”

A Review of Recent Work on the Nitrogen Metabolism of Plants, Part I

“…The absence of a number of amino-acids invariably found in protein decomposition indicates that the compounds set free from the infected plants are not due to the decay of the nodules or of the roots. It has also been shown (Virtanen et al 1933;Thornton & Nicol, 1934) that these compounds can be used by non-leguminous plants growing in association with the legume. Red and white clover have also been shown by Virtanen & von Hausen (1931) to grow much better in sterile solution if supplied with amino-acids than with ammonium salts or nitrates.…”

Some factors influencing the growth and respiration of rhizobium

“…Virtonen and von Hausen (45) found that the nodulo bacteria are more sensitive to acidity than their host plants. According to their results the optiniuta reaction for the growth of rhizobia is from pH 6.5 to 7.5j v/hile the optiinum for the culture of the legume host plants is about pH 6.5. liVriglit (56) and Stevens (40) found a variation in the acid tolerance of different strains of these organisms v/ithin a single species.…”