Publication Date


Advisor(s) - Committee Chair

Frank Toman, Ernest Beal, Alan Yungbluth, David Hartman

Degree Program

Department of Biology

Degree Type

Master of Science


The nitrate ion specific electrode has been used to measure nitrate concentration in plant tissue. Nitrate concentration, as nitrate ion activity, can be read rather simply in an aqueous extract of the plant tissue in somewhat the sane manner as a pH measurement would be taken, In contract to more time consuming chemical methods.

A previous study of nitrate concentrations in barley treated with the growth retardant chemical, B-Nine (succinic acid 2, 2 dimethylhydrazide), had been carried out by the colorimetric method of Wooley, Hicks and Hageman. The study indicated lower nitrate concentrations in treated plants, as compared with untreated controls (9).

During attempts to repeat these findings, using the nitrate electrode rather than the colorimetric method, some questions arose concerning the reliability of the nitrate electrode method. Particularly at these low concentration levels, one of the questions concerned the interfering effect of B-Nine on the nitrate electrode. During experiments testing for B-Nine interference it was observed that millivolt readings for standard sodium nitrate solutions sometimes varied considerably. It was not known if this type of fluctuation varied with the length of time since electrode renewal or even if this fluctuation was a characteristic of all nitrate electrodes.

The present study was undertaken in order to evaluate the nitrate electrode or dependability, accuracy and to determine the conditions of use under which optimum results could be obtained.


Biology | Botany | Life Sciences | Plant Sciences