@article{morgan_jackson_1976, title={CALCIUM AND MAGNESIUM IN RYEGRASS SOME DIFFERENCES IN ACCUMULATION BY ROOTS AND IN TRANSLOCATION TO SHOOTS}, volume={44}, ISSN={["0032-079X"]}, DOI={10.1007/BF00011381}, number={3}, journal={PLANT AND SOIL}, author={MORGAN, MA and JACKSON, WA}, year={1976}, pages={623–637} }
 @article{morgan_volk_jackson_1973, title={SIMULTANEOUS INFLUX AND EFFLUX OF NITRATE DURING UPTAKE BY PERENNIAL RYEGRASS}, volume={51}, ISSN={["0032-0889"]}, DOI={10.1104/pp.51.2.267}, abstractNote={Experiments with intact plants of Lolium perenne previously grown with (14)NO(3) (-) revealed significant efflux of this isotopic species when the plants were transferred to solutions of highly enriched (15)NO(3) (-). The exuded (14)NO(3) (-) was subsequently reabsorbed when the ambient solutions were not replaced. When they were frequently replaced, continual efflux of the (14)NO(3) (-) was observed. Influx of (15)NO(3) (-) was significantly greater than influx of (14)NO(3) (-) from solutions of identical NO(3) (-) concentration. Transferring plants to (14)NO(3) (-) solutions after a six-hour period in (15)NO(3) (-) resulted in efflux of the latter. Presence of Mg(2+), rather than Ca(2+), in the ambient (15)NO(3) (-) solution resulted in a decidedly increased rate of (14)NO(3) (-) efflux and a slight but significant increase in (15)NO(3) (-) influx. Accordingly, net NO(3) (-) influx was slightly depressed. A model in accordance with these observations is presented; its essential features include a passive bidirectional pathway, an active uptake mechanism, and a pathway for recycling of endogenous NO(3) (-) within unstirred layers from the passive pathway to the active uptake site.}, number={2}, journal={PLANT PHYSIOLOGY}, author={MORGAN, MA and VOLK, RJ and JACKSON, WA}, year={1973}, pages={267–272} }