Auxin transport affects a variety of important growth and developmental processes in plants, including the regulation of shoot and root branching. The asymmetrical localization of auxin influx and efflux carriers within the plasma membrane establishes the auxin gradient and facilitates its transport. REH1, a rice EIR1 (Arabidopsis ethylene insensitive root 1)-like gene, is a putative auxin effl...

Root nitrate uptake is well known to adjust to the plant's nitrogen demand for growth. Long-distance transport and/or root storage pools are thought to provide negative feedback signals regulating root uptake. We have characterized a vascular specific nitrate transporter belonging to the high-affinity Nitrate Transporter2 (NRT2) family, OsNRT2.3a, in rice (Oryza sativa ssp. japonica 'Nipponbare...

Previous work with the fluorescent Ca probe chlorotetracycline (CTC) showed that salinity displaces Ca from membranes of root cells. Using a variety of indirect approaches, we studied whether salinity displaces Ca from the cell surface or from internal membranes of corn (Zea mays L. cv Pioneer 3377) root protoplasts. Preloading the cells with supplemental Ca counteracted subsequent NaCl effects...

Plants employ a specialized transport system composed of separate influx and efflux carriers to mobilize the plant hormone auxin between its site(s) of synthesis and action. Mutations within the permease-like AUX1 protein significantly reduce the rate of carrier-mediated auxin uptake within Arabidopsis roots, conferring an agravitropic phenotype. We are able to bypass the defect within auxin up...

BACKGROUND AND AIMS In spite of major breakthroughs in the last three decades in the identification of root nitrate uptake transporters in plants and the associated regulation of nitrate transport activities, a simplified and operational modelling approach for nitrate uptake is still lacking. This is due mainly to the difficulty in linking the various regulations of nitrate transport that act a...

Silver nanoparticles (Ag NPs) are the world's most important nanomaterial and nanotoxicant. The aim of this study was to determine the early stages of interactions between Ag NPs and plant cells, and to investigate their physiological roles. We have shown that the addition of Ag NPs to cultivation medium, at levels above 300 mg L(-1) , inhibited Arabidopsis thaliana root elongation and leaf exp...

Maize (Zea mays L.) shows a high accumulation of silicon (Si), but transporters involved in the uptake and distribution have not been identified. In the present study, we isolated two genes (ZmLsi1 and ZmLsi6), which are homologous to rice influx Si transporter OsLsi1. Heterologous expression in Xenopus laevis oocytes showed that both ZmLsi1 and ZmLsi6 are permeable to silicic acid. ZmLsi1 was ...

Extracellular ATP (eATP) has been reported to be involved in plant growth as a primary messenger in the apoplast. Here, roots of Arabidopsis thaliana seedlings growing in jointed medium bent upon contact with ATP-containing medium to keep away from eATP, showing a marked avoidance response. Roots responded similarly to ADP and bz-ATP but did not respond to AMP and GTP. The eATP avoidance respon...

Extracellular purine nucleotides are implicated in the control of plant development and stress responses. While extracellular ATP is known to activate transcriptional pathways via plasma membrane (PM) NADPH oxidase and calcium channel activation, very little is known about signal transduction by extracellular ADP. Here, extracellular ADP was found to activate net Ca(2+) influx in roots of Arabi...

Increasing evidence shows that partial nitrate nutrition (PNN) can be attributed to improved plant growth and nitrogen-use efficiency (NUE) in rice. Nitric oxide (NO) is a signalling molecule involved in many physiological processes during plant development and nitrogen (N) assimilation. It remains unclear whether molecular NO improves NUE through PNN. Two rice cultivars (cvs Nanguang and Elio)...