THE FUNCTION OF MANGANESE IN THE ASSIMILATION OF NITRATES

Abstract

Soybean plants were grown in Shive''s R5S2 soln. and in a Ca(NO3)2 soln. with an oil layer on top to exclude the O2 of the air. Nitrites in large quantities, 0.5-1+ ppm. or oxygen values measured by the micro-Winkler test, 20-100 ppm., accumulated in such solns. The plants in these solns. showed yellow leaves indicating N deficiency and brown roots indicating O2 shortage. The introduction of Mn salt into these solns. prevented the accumulation of nitrites and allowed the plants to grow in a healthy manner for the time of the expt.; the tops were green and the roots silvery white. This work supports that of those who hold that Mn is a catalyst without which the orderly reduction of nitrate to amino compounds either does not take place or is greatly reduced in speed.