Importance of plasmalemma H+-ATPase activity for N losses from intact roots of spring wheat (Triticum aestivum L.)

Rroço, Evan; Kosegarten, Harald; Mengel, K.

doi:10.1016/s1161-0301(01)00123-x

Cited by 6 publications

(10 citation statements)

References 26 publications

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“…The inhibitors used were carbonylcyanide-m-chlorophenyl hydrazone (CCCP) used alone at 10 or 50 µM and applied at pH 6.0-6.5, and sodium orthovanadate (vanadate) and Nethylmaleimide (NEM) which were used separately or in combination at 0.2 or 1 mM. These inhibitors are commonly used in the same range of concentrations and durations of exposure as those to block metabolically active processes like amino acid influx on entire plant roots (Cerezo et al 2001 (CCCP used at 10 µM for 1 h); DiTomaso et al 1992 (CCCP used at 20 µM for 2 h); Jones and Darrah 1994 (NEM used at 0.5 mM for 30 min); Persson and Näsholm 2002 (CCCP used at 50 µM for 30 min); Phillips et al 2004 (CCCP used at 10 µM applied during a period range from 1 to 25 h); Rroço et al 2002 (vanadate used at 0.5 mM for 48 h)). CCCP was used as a protonophore preventing the H + gradient formation and consequently inhibiting the electrochemical pumps that require an H + gradient (DiTomaso et al 1992;Rroço et al 2002).…”

Section: Experiments 3 (Effect Of Metabolic Inhibitors)mentioning

confidence: 99%

“…However, such a gradient should increase the proportion of amino acids in root exudates such as aspartate and glutamate which are negatively charged at cellular pH, and decrease the proportion of neutral and basic amino acids like glycine, serine or arginine. Use of metabolic inhibitors has also supported the concept of passive efflux of amino acids from the roots, but most of the data have been obtained by the measurement of net exudation where influx and efflux were not measured separately (Jones and Darrah 1994;Rroço et al 2002) and the mechanism of amino acid efflux itself has not been investigated so far.…”

Section: Introductionmentioning

confidence: 99%

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Characterisation of root amino acid exudation in white clover (Trifolium repens L.)

Lesuffleur

Cliquet

2010

Plant Soil

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The mechanism of root amino acid exudation was studied in white clover (Trifolium repens L.) to explain the apparent selectivity of this process resulting in contrasted amino acid profiles between root tissues and root exudates. Asparagine is generally recovered in low proportions in root exudates but represent a major fraction of amino acids in root tissues, and the opposite is found for glycine. Amino acid profiles were studied in two potential sites of intense exudation, root tips and nodules, and a 15 N labelling method was used to compare influxes and effluxes of different amino acids. Metabolic inhibitors were used to test the assumption that amino acid exudation is a passive process. We observed that amino acid profiles were similar between whole roots, root tips and nodules. Influxes of asparagine and glycine were in the same range, but efflux of glycine largely exceeded efflux of asparagine. Metabolic inhibitors strongly reduced glycine influx and modified glycine efflux. It is concluded that the selectivity of amino acid exudation is not explained by the composition of putative intense sites of exudation but is explained by highly contrasted effluxes between amino acids. The effect of metabolic inhibitors shows that glycine efflux occurs not only as a simple passive leakage. These results suggest that amino acid exudation is a plant-controlled process.

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Section: Experiments 3 (Effect Of Metabolic Inhibitors)mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Characterisation of root amino acid exudation in white clover (Trifolium repens L.)

Lesuffleur

Cliquet

2010

Plant Soil

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“…Influx is energy dependent (Ortiz-Lopez et al 2000), and amino acids, and particularly glycine, are taken up actively by plant roots even under field conditions (Streeter et al 2000;Näsholm et al 2001;Miller and Bowman 2003). Root efflux of amino acids is thought to occur by passive diffusion (Rroço et al 2002), and further work is required to achieve a better understanding of the efflux process (Phillips et al 2004).…”

Section: Introductionmentioning

confidence: 99%

“…Collection of exudates during a long period (more than 1 h) has probably led to underestimation of efflux because of re-uptake of previously exuded amino acids (Jones and Darrah 1994;Phillips et al 2004). Furthermore high exogenous amino acid concentrations used compared to those found in soils (in the mM range; Raab et al 1996;Jones et al 2002;Szajdak et al 2003) may have stimulated influx and diminished efflux which is supposed to be concentration dependant (Shepherd and Davies 1994;Rroço et al 2002). Use of 15 N-labelled nitrate fed to plants during short period has allowed separate measurement of nitrate influx and efflux (Morgan et al 1973).…”

Section: Introductionmentioning

confidence: 99%

Root amino acid exudation: measurement of high efflux rates of glycine and serine from six different plant species

et al. 2007

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Amino acid concentration in the rhizosphere results from fluxes between plant roots, soil and microorganisms. In this context, root amino acid exudation process, composed of both efflux and influx, remains unclear. One main issue is to understand the selectivity of amino acid exudation resulting mainly in high proportions of glycine and serine in exudates compared to low proportions inside the root. To reach this point, a quantitative analysis of exudation with dissociated measurements of efflux from influx is needed. We measured efflux and influx by supplying 15 N-labelled glycine or serine for a short time of exposure at ecologically relevant concentrations to plants of white clover (Trifolium repens L.), perennial ryegrass (Lolium perenne L.), maize (Zea mays L.), oilseed rape (Brassica napus L.), tomato (Lycopersicon esculentum Mill.) and alfalfa (Medicago sativa L.). Efflux was estimated by the increase of 14 N content of amino acids in root exudates and influx was estimated by the increase of 15 N content in plant tissue. Glycine efflux exceeded influx for all six species and was much higher in Fabaceae than in Poaceae. Serine efflux exceeded influx in alfalfa, white clover and rape. We conclude that presence of glycine and serine in root bathing solutions results from high glycine and serine efflux rates, observed in all six species studied here. The physiological and ecological significances of these high efflux rates are discussed in the context of N metabolism and plantsoil-microorganisms interactions.

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“…Of the low molecular weight root exudates, sugars, organic acids and amino acids form the dominant components (Aulakh et al, 2001). Sugars, organic acids and amino acids effl ux from roots is thought to occur by passive diff usion (Jones and Darrah, 1994; Shepher and Davies, 1994;Rroço et al, 2002;Uren, 2007;Neumann and Römheld, 2007). With age of plants, the amount of organic acids in root exudates increased and the proportion of sugars and amino 442 V. Vranová, H. Kaňová, K. Rejšek, P. Formánek acids decreased, expressed per weight unit of root dry weight (Smith, 1970;Aulakh et al, 2001;Gransee and Wittenmayer, 2000;Uren, 2007).…”

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confidence: 99%

Dominant amino acids, organic acids and sugars in water-soluble root exudates of C<sub>4</sub> plants: a mini-review

Vranová¹,

Kaňová²,

Rejšek³

et al. 2014

Acta Univ. Agric. Silvic. Mendelianae Brun.

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VRANOVÁ, V., KAŇOVÁ, H., REJŠEK, K., FORMÁNEK, P.: Dominant amino acids, organic acids and sugars in water-soluble root exudates of C 4 plants: a mini-review. Acta univ. agric. et silvic. Mendel. Brun., 2010, LVIII, No. 5, pp. 441-446 The aim of this mini-review was to identify the dominant carbohydrates, organic acids and amino acids in water-soluble root exudates of plants which represent dominant compounds there. The study is focused on plants of C 4 -type of metabolism taking into account available literature. From group of carbohydrates, those dominant are represented glucose, fructose, arabinose and sucrose. Between dominant amino acids occurring in root exudates of C 4 -metabolism plants are alanine, se rine, arginine, glutamine, glutamic and aspartic acid, glycine, proline, cystine, lysine and -aminobutyric acid. Citric, malic, tartaric, succinic, trans-aconitic represent the dominant organic acids. This knowledge may be useful for planning analyses of these compounds in root exudates of C 4 plants. Except ), amino acids, amides, sugars, aliphatic acids, aromatic acids, volatile aromatic compounds, gases such as ethylene, vitamins, peptides, proteins, enzymes, plant hormones, alcohols, ketones, olefi ns, urea, phytoalexins (Curl and Truelove, 1986;Vančura, 1988;Grayston et al., 1996;Paynel et al., 2001;Uren, 2007;Neumann and Römheld, 2007). Oxidative enzymes assessed in root exudates were e.g. haem-containing peroxidases, unspecifi c coper-containing oxida ses, monooxygenases-hydroxylating and aromatic-ring cleavage dioxygenases (Gramss and Rudeschko, 1998). In total, 200 diff erent carbon containing molecules are present in root exudates (Curl and Truelove, 1986), and up to 40 % of the net carbon fi xed during photosynthesis can be released into the rhizosphere Lynch, 1983, 1990). Root exudates can be sectioned according to their chemical character, properties and molecular weight (Rovira, 1956;1969). Commonly, root exudates are divided into high molecular weight waterinsoluble materials such as cell walls, sloughed-off material, other root debris and mucilage, and low molecular weight compounds denoted as water-solu ble exudates such as sugars, amino acids, organic acids, hormones and vitamins (Rovira et al., 1979;Cheng et al., 1993; Traoré et al., 2000). Of the low molecular weight root exudates, sugars, organic acids and amino acids form the dominant components (Aulakh et al., 2001). Sugars, organic acids and amino acids effl ux from roots is thought to occur by passive diff usion (Jones and Darrah, 1994; Shepher and Davies, 1994;Rroço et al., 2002;Uren, 2007;Neumann and Römheld, 2007). With age of plants, the amount of organic acids in root exudates increased and the proportion of sugars and amino 442 V. Vranová, H. Kaňová, K. Rejšek, P. Formánek acids decreased, expressed per weight unit of root dry weight (Smith, 1970;Aulakh et al., 2001;Gransee and Wittenmayer, 2000;Uren, 2007). The intensity of exudation related to unit of root biomass was found to decrease with age of plant...

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Importance of plasmalemma H+-ATPase activity for N losses from intact roots of spring wheat (Triticum aestivum L.)

Cited by 6 publications

References 26 publications

Characterisation of root amino acid exudation in white clover (Trifolium repens L.)

Characterisation of root amino acid exudation in white clover (Trifolium repens L.)

Root amino acid exudation: measurement of high efflux rates of glycine and serine from six different plant species

Dominant amino acids, organic acids and sugars in water-soluble root exudates of C<sub>4</sub> plants: a mini-review

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