NH4+-stimulated and -inhibited components of K+ transport in rice (Oryza sativa L.)
Open Access
- 4 July 2008
- journal article
- research article
- Published by Oxford University Press (OUP) in Journal of Experimental Botany
- Vol. 59 (12), 3415-3423
- https://doi.org/10.1093/jxb/ern190
Abstract
The disruption of K+ transport and accumulation is symptomatic of NH4+ toxicity in plants. In this study, the influence of K+ supply (0.02–40 mM) and nitrogen source (10 mM NH4+ or NO3–) on root plasma membrane K+ fluxes and cytosolic K+ pools, plant growth, and whole-plant K+ distribution in the NH4+-tolerant plant species rice (Oryza sativa L.) was examined. Using the radiotracer 42K+, tissue mineral analysis, and growth data, it is shown that rice is affected by NH4+ toxicity under high-affinity K+ transport conditions. Substantial recovery of growth was seen as [K+]ext was increased from 0.02 mM to 0.1 mM, and, at 1.5 mM, growth was superior on NH4+. Growth recovery at these concentrations was accompanied by greater influx of K+ into root cells, translocation of K+ to the shoot, and tissue K+. Elevating the K+ supply also resulted in a significant reduction of NH4+ influx, as measured by 13N radiotracing. In the low-affinity K+ transport range, NH4+ stimulated K+ influx relative to NO3– controls. It is concluded that rice, despite its well-known tolerance to NH4+, nevertheless displays considerable growth suppression and disruption of K+ homeostasis under this N regime at low [K+]ext, but displays efficient recovery from NH4+ inhibition, and indeed a stimulation of K+ acquisition, when [K+]ext is increased in the presence of NH4+.Keywords
This publication has 57 references indexed in Scilit:
- Alleviation of rapid, futile ammonium cycling at the plasma membrane by potassium reveals K+-sensitive and -insensitive components of NH4+ transportJournal of Experimental Botany, 2008
- Potassium transporters in plants – Involvement in K+ acquisition, redistribution and homeostasisFEBS Letters, 2007
- The cytosolic Na+ : K+ ratio does not explain salinity‐induced growth impairment in barley: a dual‐tracer study using 42K+ and 24Na+Plant, Cell & Environment, 2006
- Rapid, Futile K+ Cycling and Pool-Size Dynamics Define Low-Affinity Potassium Transport in BarleyPlant Physiology, 2006
- High-Affinity Potassium Transport in Barley Roots. Ammonium-Sensitive and -Insensitive PathwaysPlant Physiology, 2000
- Potassium Uptake Supporting Plant Growth in the Absence of AKT1 Channel ActivityThe Journal of general physiology, 1999
- Potassium fractions with other nutrients in crops: A review focusing on the tropicsJournal of Plant Nutrition, 1994
- Molecular Heterogeneity of Photosystem I (psaD, psaE, psaF, psaH, and psaL Are All Present in Isoforms in Nicotiana spp.)Plant Physiology, 1993
- Potassium Influx into Maize Root SystemsPlant Physiology, 1987
- Influence of abscisic acid on unidirectional fluxes and intracellular compartmentation of K+ and Na+ in excised barley root segmentsPhysiologia Plantarum, 1981