Electrophysiological factors in the influence of nitrate and ammonium ions on calcium uptake and translocation in tomato plants

摘要: Tomato plants (Lycopersicon esculentum Mill. cv. San Marzano), grown in dilute nutrient solutions containing (in meq ˙ 1-1) 0.5 NaNO3, NH4NO3 or 0.25 (NH4)2 SO4 as the nitrogen source, were detopped for collection of xylem sap and measurement trans-root electrical potentials. The plant parts exudate subsequently analysed mineral content. commonly observed effects NH4+ noted, including reduction calcium concentration sap, content stems leaves, compared with NO3-fed plants. This effect was attributed principally to less negative potential measured NH4+-fed plants, resultant inward driving force on passively moving divalent cations.