TY - JOUR
AU1 - LEE, R., B.
AU2 - DREW, M., C.
AB - Abstract Influx of nitrate into the roots of intact barley plants was followed over periods of 1–15 min using nitrogen-13 as a tracer. Based on measurements taken over 15 min from a range of external nitrate concentrations (0·2–250 mmol m−3), the kinetic parameters of influx, Imax and Km, were calculated. Compared with plants grown in the presence of nitrate throughout, plants that had been starved of N for 3 d showed a significantly greater value ofImax for 13N-nitrate influx (by a factor of 1·4–1·8), but a similar value of Km (12–14 mmol m−3). Pre-treating N-starved plants with nitrate for about 5 h further increased the subsequent rate of 13N-nitrate influx, but had little effect in the unstarved controls. Allowing for this induction of additional nitrate transport, the difference in rates of nitrate influx in control and N-starved plants was sufficient to account for the previously-observed difference in net uptake by the two groups of plants. In barley plants grown without any exposure to nitrate, but with ammonium as N-source, both Imax and Km for subsequent 13N-nitrate influx were significantly decreased (by about one-half) compared with the corresponding nitrate-grown controls. The importance of changes in the rate of influx in the regulation of net uptake of nitrate is discussed. Ion transport, nitrate, influx, kinetic parameters, N-deficiency This content is only available as a PDF. © Oxford University Press
TI - Nitrogen-13 Studies of Nitrate Fluxes in Barley RootsII. EFFECT OF PLANT N-STATUS ON THE KINETIC PARAMETERS OF NITRATE INFLUX
JF - Journal of Experimental Botany
DO - 10.1093/jxb/37.12.1768
DA - 1986-12-01
UR - https://www.deepdyve.com/lp/oxford-university-press/nitrogen-13-studies-of-nitrate-fluxes-in-barley-rootsii-effect-of-C3FVNAqNed
SP - 1768
VL - 37
IS - 12
DP - DeepDyve
ER -