Igit] SCHREINER & SULLIVAN—REDUCTION BY ROOTS 125 
sodium nitroprusside and sodium or ammonium hydroxide. The 
crushed wheat roots or seedlings do not give this reaction. Accord- 
ing to HEFFTER, non-reducing albumins can be changed to reducing 
albumins by treatment with a 10 per cent sodium sulphite solu- 
tion for 12-24 hours and will then give the nitroprusside reaction. 
Wheat seedlings of different stages of development from three 
to ten days old were rapidly crushed, covered with a 10 per cent 
solution of sodium sulphite, and kept at 40° C., with repeated shak- 
ing. The solutions with suspended matter were tested after 2, 6, 
and 24 hours, and at no time gave the nitroprusside reaction for the 
sulphydryl group nor did they reduce sulphur. In 24 hours the 
seedling pulp was tested for the sulphydryl group with negative 
results, and the pulp formed no hydrogen sulphide from freshly 
precipitated sulphur. 
NITRATES.—To test the power of wheat seedlings to reduce 
nitrates to nitrites, the wheat grains were treated with a 0.1 per cent 
solution of mercuric chloride for 30 minutes, and the seeds, well 
washed with sterile water, were placed in sterile tubes containing a 
little water. In the tubes tightly closed with cotton the wheat ger- 
minated and grew well. There were added to each tube to cc. of a 
I per cent solution of potassium nitrate, and after 24 hours the 
solution was tested for nitrites by means of Griess reagents (27), 
sulphanilic acid and naphthylamine acetate. The ungerminated 
seeds, whether sterilized or not, did not give the nitrite test under 
these conditions. The solutions containing the seedlings, on the 
other hand, gave good tests for nitrites. The ability of sterile seeds 
germinated in tubes to form nitrites from nitrates was tested several 
times, both in air and in vacuum. Sometimes a fair amount of 
nitrite was formed, in one case as high as 6 parts per million, 
sometimes the amount was very little. It should be borne in mind, 
however, that nitrites are absorbed by plants. The formation 
of nitrites was greater in vacuum. It would seem that a nitrate- 
reducing power appears in the early stages of the wheat seedling, 
but is not in the seed at rest. The formation of nitrites is small, 
and no culture tests were made to show that microorganisms were 
entirely excluded in the experiment. It may be said, however, 
that enzymes capable of reducing nitrates have been reported in 
