Abstract

Receive: RSS Feeds, eTOCs, free email alerts (when new articles cite this article), more» Information about commercial reprint orders: http://jb.asm.org/site/misc/reprints.xhtml To subscribe to to another ASM Journal go to: http://journals.asm.org/site/subscriptions/ III. RESPIRATION AND GROWTH AS INFLUENCED BY THE REACTION OF THE MEDIUM1 Iowa State College, Ames, Iowa Received for publication January 9, 1935 Downloaded from http://jb.asm.org/ on December 10, 2011 by deepdyve Several investigations have been reported concerning the effect of hydrogen ion concentration on the growth and longevity of rhizobia in the soil and in liquid cultures. Fred, Baldwin and McCoy (1932) have presented a summary of this topic. Although there are some differences of opinion, it has been found, in general, that the various species of these organisms are affected differently by acidity but have about the same tolerance to alkalinity. Rhizobium meliloti is the most sensitive to acidity and is favored by a neutral or slightly alkaline reaction. Rh. lupini and Rh. japonicum are the most tolerant to acidity and therefore they will grow at a lower pH than the other species of this genus. No work has been reported concerning the specific effects of pH upon the physiological activities of these organisms other than