@article{henry_raper_rideout_1992, title={ONSET OF AND RECOVERY FROM NITROGEN STRESS DURING REPRODUCTIVE GROWTH OF SOYBEAN}, volume={153}, ISSN={["1058-5893"]}, DOI={10.1086/297020}, abstractNote={Photosynthetic rates and allocation of dry matter, nitrogen, and nonstructural carbohydrates were determined during onset of and recovery from a nitrogen stress for reproductive soybean (Glycine max [L.] Merrill cv Ransom) plants. Until the beginning of seed fill, non-nodulated plants were grown in flowing solution culture with 1.0 mM NO-3 in a complete nutrient solution. One set of plants then was transferred to minus-nitrogen solution for 24 d of seed fill; a second set was transferred to a minus-nitrogen solution for 14 d followed by return to the complete solution with 1.0 mM NO-3 for the remaining 10 d of seed fill; and a third set was continued on the complete solution. Net CO2 exchange rates of individual leaves, which remained nearly constant during seed fill for nonstressed plants, declined at an accelerated rate during onset of nitrogen stress as the specific content of reduced nitrogen in the leaves was decreased by remobilization of nitrogen to support pod growth. The rate of nitrogen remobilization out of leaves initially was relatively greater than the decrease in photosynthetic rate. While rate of pod growth declined in response to the developing nitrogen stress, photosynthetic assimilation of carbon exceeded reproductive demand and nonstructural carbohydrates accumulated within tissues. Following resupply of exogenous NO-3, specific rate of NO-3 uptake by roots was enhanced relative to nonstressed plants. While there was little increase in content of reduced nitrogen in leaves, net remobilization of nitrogen out of leaves ceased, and the decline in photosynthetic rate stabilized at about 51% of that for nonstressed plants. This level of photosynthesis, combined with the availability of elevated pools of carbohydrates accumulated during stress, was sufficient to support the increases in both the specific rates of NO-3 uptake and the rate of pod growth during recovery.}, number={2}, journal={INTERNATIONAL JOURNAL OF PLANT SCIENCES}, author={HENRY, LT and RAPER, CD and RIDEOUT, JW}, year={1992}, month={Jun}, pages={178–185} }
 @article{henry_raper_1991, title={Soluble carbohydrate allocation to roots, photosynthetic rate of leaves, and nitrate assimilation as affected by nitrogen stress and irradiance}, volume={152}, number={1}, journal={Botanical Gazette (Chicago)}, author={Henry, L. T. and Raper, C. D., Jr.}, year={1991}, pages={23} }
 @article{henry_raper_1989, title={CYCLIC VARIATIONS IN NITROGEN UPTAKE RATE OF SOYBEAN PLANTS - AMMONIUM AS A NITROGEN-SOURCE}, volume={91}, ISSN={["0032-0889"]}, DOI={10.1104/pp.91.4.1345}, abstractNote={When 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.}, number={4}, journal={PLANT PHYSIOLOGY}, author={HENRY, LT and RAPER, CD}, year={1989}, month={Dec}, pages={1345–1350} }
 @article{henry_raper_1989, title={EFFECTS OF ROOT-ZONE ACIDITY ON UTILIZATION OF NITRATE AND AMMONIUM IN TOBACCO PLANTS}, volume={12}, ISSN={["0190-4167"]}, DOI={10.1080/01904168909363995}, abstractNote={Tobacco (Nicotiana tabacum L., cv. 'Coker 319') plants were grown for 28 days in flowing nutrient culture containing either 1.0 mM NO3- or 1.0 mM NH4+ as the nitrogen source in a complete nutrient solution. Acidities of the solutions were controlled at pH 6.0 or 4.0 for each nitrogen source. Plants were sampled at intervals of 6 to 8 days for determination of dry matter and nitrogen accumulation. Specific rates of NO3- or NH4+ uptake (rate of uptake per unit root mass) were calculated from these data. Net photosynthetic rates per unit leaf area were measured on attached leaves by infrared gas analysis. When NO3- [correction of NO-] was the sole nitrogen source, root growth and nitrogen uptake rate were unaffected by pH of the solution, and photosynthetic activity of leaves and accumulation of dry matter and nitrogen in the whole plant were similar. When NH4+ was the nitrogen source, photosynthetic rate of leaves and accumulation of dry matter and nitrogen in the whole plant were not statistically different from NO3(-) -fed plants when acidity of the solution was controlled at pH 6.0. When acidity for NH4(+) -fed plants was increased to pH 4.0, however, specific rate of NH4+ uptake decreased by about 50% within the first 6 days of treatment. The effect of acidity on root function was associated with a decreased rate of accumulation of nitrogen in shoots that was accompanied by a rapid cessation of leaf development between days 6 and 13. The decline in leaf growth rate of NH4(+) -fed plants at pH 4.0 was followed by reductions in photosynthetic rate per unit leaf area. These responses of NH4(+) -fed plants to increased root-zone acidity are characteristic of the sequence of responses that occur during onset of nitrogen stress.}, number={7}, journal={JOURNAL OF PLANT NUTRITION}, author={HENRY, LT and RAPER, CD}, year={1989}, pages={811–826} }