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Cyclic variations in nitrogen uptake rate of soybean plants: ammonium as a nitrogen sourceWhen NO3- is the sole nitrogen source in flowing solution culture, the net rate of nitrogen uptake by nonnodulated soybean (Glycine max L. Merr. cv Ransom) plants cycles between maxima and minima with a periodicity of oscillation that corresponds with the interval of leaf emergence. Since soybean plants accumulate similar quantities of nitrogen when either NH4+ or NO3- is the sole source in solution culture controlled at pH 6.0, an experiment was conducted to determine if the oscillations in net rate of nitrogen uptake also occur when NH4+ is the nitrogen source. During a 21-day period of vegetative development, net uptake of NH4+ was measured daily by ion chromatography as depletion of NH4+ from a replenished nutrient solution containing 1.0 millimolar NH4+. The net rate of NH4+ uptake oscillated with a periodicity that was similar to the interval of leaf emergence. Instances of negative net rates of uptake indicate that the transition between maxima and minima involved changes in influx and efflux components of net NH4+ uptake.
Document ID
20040112076
Document Type
Reprint (Version printed in journal)
Authors
Henry, L. T. (North Carolina State University Raleigh 27695)
Raper, C. D. Jr
Date Acquired
August 21, 2013
Publication Date
January 1, 1989
Publication Information
Publication: Plant physiology
Volume: 91
ISSN: 0032-0889
Subject Category
Life Sciences (General)
Funding Number(s)
CONTRACT_GRANT: NCC2-101
Distribution Limits
Public
Copyright
Other
Keywords
NASA Discipline Life Support Systems
NASA Program CELSS
NASA Discipline Number 61-10
Non-NASA Center