The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Mar. 17, 1992
Filed:
Mar. 19, 1991
David B Layzell, Kingston, CA;
Stephen Hunt, Kingston, CA;
Gerry Palmer, Sydenham, CA;
R Ford Denison, Beaver, WV (US);
Abstract
A non-invasive method and apparatus are described for measuring the oxygen concentration in the infected cells of the nodules of nitrogen fixing plants in the laboratory or field. In many cases, this information can be used to estimate the nitrogenase activity, and therefore the nitrogen fixation rate, in these nodules since recent studies have shown that the oxygen concentration limits and controls nitrogenase activity under most environmental conditions. Using the same apparatus, a method to measure nodule respiration and nodule oxygen permeability is also described. The nodule oxygen concentration in the infected cells of nodules is maintained at very low levels and has not been measurable previously by non-invasive techniques. The fractional oxygenation of plant hemoglobin is measured spectroscopically using one or more modulated light sources, a number of optical fibres to convey the light to and from the nodules, a photodetector to measure the light passing through the nodule and a detection system such as a photodiode coupled to a microcomputer or a lock-in amplifier to process the output signal.