@article{feng_volk_jackson_1998, title={Source and magnitude of ammonium generation in maize roots}, volume={118}, ISSN={["0032-0889"]}, DOI={10.1104/pp.118.3.835}, abstractNote={Abstract}, number={3}, journal={PLANT PHYSIOLOGY}, author={Feng, JN and Volk, RJ and Jackson, WA}, year={1998}, month={Nov}, pages={835–841} }
 @article{jackson_volk_1995, title={ATTRIBUTES OF THE NITROGEN UPTAKE SYSTEMS OF MAIZE (ZEA-MAYS L) - MAXIMAL SUPPRESSION BY EXPOSURE TO BOTH NITRATE AND AMMONIUM}, volume={130}, ISSN={["0028-646X"]}, DOI={10.1111/j.1469-8137.1995.tb01827.x}, abstractNote={summary}, number={3}, journal={NEW PHYTOLOGIST}, author={JACKSON, WA and VOLK, RJ}, year={1995}, month={Jul}, pages={327–335} }
 @article{jackson_chaillou_morotgaudry_volk_1993, title={ENDOGENOUS AMMONIUM GENERATION IN MAIZE ROOTS AND ITS RELATIONSHIP TO OTHER AMMONIUM FLUXES}, volume={44}, ISSN={["0022-0957"]}, DOI={10.1093/jxb/44.4.731}, abstractNote={An investigation to determine the magnitude of the back reactions which occur during net ammonium uptake by roots and during net ammonium assimilation within roots was undertaken with maize (Zea mays L.). Ten-day-old seedlings, which had been grown on 250 mmol m~3 ammonium at pH 4 or 6, were pretreated for 3 h in the absence or presence of 500 mmol m3 MSX (methionine-DL-sulphoximine), an inhibitor of the glutamine synthetase-catalysed pathway of ammonium assimilation. They were then exposed for 2 h to 99 A% 15N-ammonium + MSX. Substantial ammonium cycling occurred during net ammonium uptake. Efflux was enhanced by MSX treatment, reflecting a 2- to 3-fold accumulation of ammonium in the root tissue. Influx of ammonium was also increased by treatment with MSX, indicating that influx was enhanced when products of ammonium assimilation were dissipated. The decline in root 14N-ammonium accounted for only a small fraction of the 14N-ammonium recovered in the ambient 15N-ammonium solution, revealing a substantial generation of endogenous 14N-ammonium during the 2 h exposure. The net quantity of ammonium generated was increased appreciably when assimilation of ammonium was restricted by MSX and it was estimated to occur at least 50% faster than net ammonium uptake. Presence of MSX severely decreased translocation of 15N to shoots but had a smaller influence on incorporation of 15N into macromolecules of the root tissue. The various ammonium flux rates were not greatly affected by growth at pH 4 0, implying a considerable resistance of ammonium assimilation processes in these maize roots to the high ambient acidity commonly induced by exposure to ammonium.}, number={261}, journal={JOURNAL OF EXPERIMENTAL BOTANY}, author={JACKSON, WA and CHAILLOU, S and MOROTGAUDRY, JF and VOLK, RJ}, year={1993}, month={Apr}, pages={731–739} }
 @article{jackson_kwik_volk_1976, title={NITRATE UPTAKE DURING RECOVERY FROM NITROGEN DEFICIENCY}, volume={36}, ISSN={["0031-9317"]}, DOI={10.1111/j.1399-3054.1976.tb03931.x}, abstractNote={Abstract}, number={2}, journal={PHYSIOLOGIA PLANTARUM}, author={JACKSON, WA and KWIK, KD and VOLK, RJ}, year={1976}, pages={174–181} }
 @article{jackson_johnson_volk_1974, title={NITRITE UPTAKE BY NITROGEN-DEPLETED WHEAT SEEDLINGS}, volume={32}, ISSN={["0031-9317"]}, DOI={10.1111/j.1399-3054.1974.tb03723.x}, abstractNote={Abstract}, number={1}, journal={PHYSIOLOGIA PLANTARUM}, author={JACKSON, WA and JOHNSON, RE and VOLK, RJ}, year={1974}, pages={37–42} }
 @article{jackson_johnson_volk_1974, title={NITRITE UPTAKE PATTERNS IN WHEAT SEEDLINGS AS INFLUENCED BY NITRATE AND AMMONIUM}, volume={32}, ISSN={["0031-9317"]}, DOI={10.1111/j.1399-3054.1974.tb03736.x}, abstractNote={Abstract}, number={2}, journal={PHYSIOLOGIA PLANTARUM}, author={JACKSON, WA and JOHNSON, RE and VOLK, RJ}, year={1974}, pages={108–114} }
 @article{jackson_flesher_hageman_1973, title={NITRATE UPTAKE BY DARK-GROWN CORN SEEDLINGS - SOME CHARACTERISTICS OF APPARENT INDUCTION}, volume={51}, ISSN={["1532-2548"]}, DOI={10.1104/pp.51.1.120}, abstractNote={Five-or six-day old seedlings of corn (Zea mays L.) were exposed to 0.25 mm Ca(NO(3))(2), 1.0 mm sodium 2-[N-morpholino]-ethanesulfonate, 5 mug Mo per liter and 50 mug of chloramphenicol per ml at pH 6. Nitrate uptake was determined from depletion of the ambient solution. The pattern of nitrate uptake was characterized, after the first 20 minutes, by a low rate which increased steadily to a maximal rate by 3 to 4 hours. Transfer of nitrate to the xylem did not totally account for the increase. Development of the maximal accelerated rate did not occur at 3 C with excised roots nor with seedlings whose endosperm had been removed. Use of CaCl(2) rather than Ca(NO(3))(2) resulted in a linear rate of chloride uptake during the first 4 hours, and chloride uptake was not as restricted by endosperm removal as was nitrate uptake.Nitrite pretreatments or the addition of cycloheximide (2 mug ml(-1)), puromycin (400 mug ml(-1)) and 6-methylpurine (0.5 mm) restricted maximal development of the accelerated nitrate uptake rate. Actinomycin D (20 mug ml(-1)) inhibited the rate only after about three hours exposure. The RNA and protein synthesis inhibitors also restricted nitrate reductase induction in the apical segments of the root tissue. The data suggest that development of the maximal accelerated rate of nitrate uptake depended upon continuous protein synthesis, and the hypothesis that synthesis of a specific nitrate transport protein must occur is advanced. But the alternative hypothesis, i.e., that induction of nitrate reductase (and/or a consequence of the act of nitrate reduction) provided the required stimulus, remains tenable.}, number={1}, journal={PLANT PHYSIOLOGY}, author={JACKSON, WA and FLESHER, D and HAGEMAN, RH}, year={1973}, pages={120–127} }