@article{feng_volk_jackson_1994, title={INWARD AND OUTWARD TRANSPORT OF AMMONIUM IN ROOTS OF MAIZE AND SORGHUM - CONTRASTING EFFECTS OF METHIONINE SULFOXIMINE}, volume={45}, ISSN={["0022-0957"]}, DOI={10.1093/jxb/45.4.429}, abstractNote={To examine the adaptive responses of ammonium efflux of nitrate-grown plants during first exposure to ammonium nutrition, isotopic flows of ammonium in and out of root tissue of maize (Zea mays L.) and sorghum (Sorghum bicolor L.) were delineated. Appreciable efflux of 14 N-ammonium occurred during the first 2 min of exposure, suggesting that ammonium efflux is characteristic of plants grown with nitrate as the sole source of nitrogen. Treatment with methionine sulphoximine (MSX) enhanced the initial 14 N-ammonium efflux 5-fold in maize but less than 2-fold in sorghum. Increasing ambient acidity from pH 6 to pH 4 had relatively little effect on 14 N-ammonium efflux in either species}, number={273}, journal={JOURNAL OF EXPERIMENTAL BOTANY}, author={FENG, JN and VOLK, RJ and JACKSON, WA}, year={1994}, month={Apr}, pages={429–439} }