Ammonium repression of nitrate reductase formation in Lemna minor L.

Orebamjo, T. O.; Stewart, George R.

doi:10.1007/bf00385401

Cited by 35 publications

(8 citation statements)

References 23 publications

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“…1b and 4b) suggest that ammonium can be an inhibitory signal. Ammonium can affect the metabolism of nitrate because most steps in plants' nitrate assimilatory pathway are nitrate-inducible but ammonium, or its metabolic products, can inhibit the reduction of nitrate (Orebamjo and Stewart 1975;Oaks et al 1977;Emmett 2007) through inhibition of NR synthesis. This hypothesis should be further assessed as a potential mechanism contributing to the natural replacement of summer semi-deciduous species by evergreen sclerophylls during plant succession (Werner et al 1999(Werner et al , 2001.…”

Section: Discussionmentioning

confidence: 99%

Patterns of nitrate reductase activity vary according to the plant functional group in a Mediterranean maquis

et al. 2011

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Since little is known about how the Mediterranean Basin ecosystems are affected by nitrogen deposition, we aimed to understand the use of nitrogen by distinct plant functional groups (PFG: summer semideciduous and evergreen sclerophylls) present in the Mediterranean maquis in order to assess which may be more affected by changes in nitrogen availability. The availability of soil inorganic nitrogen, leaf nitrate concentrations and nitrate reductase activity (in vivo and in vitro) were measured during the year in three plant species from each PFG. The patterns of in vitro NRA along the shoot and through the day were also determined. Although summer semi deciduous species occupied soil patches richer in nitrate, their leaf NRA were significantly lower than that of evergreen sclerophylls species. The pattern of nitrate and ammonium availabilities along the year also distinguished the PFG. Results show that each PFG is composed of a number of physiologically similar species. Patterns of NRA varied according to the PFG, which may represent distinct specializations of co-occurring species to access nitrogen. Therefore, the NRA can be used as an indicator of the nitrate availability taking into consideration the time of the year, the plant species and its PFG.

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Section: Discussionmentioning

confidence: 99%

Patterns of nitrate reductase activity vary according to the plant functional group in a Mediterranean maquis

et al. 2011

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“…Several authors described a distinct decrease of nitrate reductase activity when ammonium is supplied as second nitrogen form (Mtiller and Janiesch, 1993;Orebamjo and Stewart, 1975;Runge, 1983). Several authors described a distinct decrease of nitrate reductase activity when ammonium is supplied as second nitrogen form (Mtiller and Janiesch, 1993;Orebamjo and Stewart, 1975;Runge, 1983).…”

Section: Fermentative Activity and Nitrate Reductionmentioning

confidence: 99%

Influence of NO3 - and NH4 + nutrition on fermentation, nitrate reductase activity and adenylate energy charge of roots of Carex pseudocyperus L. and Carex sylvatica Huds. exposed to anaerobic nutrient solutions

Müller

Albers²,

Janiesch

1994

Plant Soil

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The adenylate energy charge, production of ethanol and lactate, and nitrate reductase activity were determined in order to study the influence of different nitrogen sources on the metabolic responses of roots of Carexpseudocyperus L. and Carex sylvatica HUDS. exposed to anaerobic nutrient solutions. Determination ofadenylates was carried out by means of a modified HPLC technique. Total quantity of adenylates was higher in Carex pseudocyperus than in Carex sylvatica under all conditions. In contrast, the adenylate energy charge was only slightly different between the species and decreased more or less in relation to the applied nitrogen source under oxygen deficiency. The adenylate energy charge in roots of plants under nitrate nutrition showed a smaller decrease under anaerobic environmental conditions than plants grown with ammonium or nitrate/ammonium. Roots of nitrate-fed plants showed a lower ethanol and lactate production than ammonium/nitrate-and ammonium-fed plants. Ethanol production was higher in C. pseudocyperus, formation of lactate was lower compared to that in Carex sylvatica. The activity of enzymes involved in fermentation processes (ADH, LDH and PDC) was enhanced significantly after 24 hours of exposure to anaerobic nutrient solutions in roots of both species. The induction of these enzymes was only slightly influenced by different nitrogen supply. In vivo nitrate reductase activity increased almost 3-fold compared to the aerobic treatment in both species and overcompensated loss of NADH reoxidation capacity caused by decrease of ethanol and lactate development. Induction of in vitro nitrate reductase activity was enhanced 313% in C. pseudocyperus and 349% in C. sylvatica under anaerobic environmental conditions and nitrate supply. These results indicate that nitrate may serve as an alternative electron acceptor in anaerobic plant root metabolism and that the nitrate-supported energy charge may be due to an accelerated glycolytic flux resulting from a more effective NADH reoxidation capacity by nitrate reduction plus fermentation than by fermentation alone.Abbreviations: ADH-alcohol dehydrogenase, AEC-adenylate energy charge, DMSO-dimethyl sulfoxide, EDTAethylen diamine tetraacetic acid, HPLC-high performance liquid chromatography, LDH-lactate dehydrogenase, NRA-nitrate reductase activity, PCA-perchloric acid, PDC-pyruvate decarboxylase, PVP-polyvinylpyrrolidone, PVPP-polyvinylpolypyrrolidone, TCA-trichloroacetic acid, Tris-tris(hydroxymethyl)aminomethane.

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“…When examining at the molecular level the phytohormone-mediated effect of the nitrogen status of a plant on its growth strategy it was obvious that a nitrogen metabolism enzyme is chosen. On the other hand, ammonium in many cases represses nitrate reductase synthesis (Syrett and Morris, 1963;Orebanjo and Stewart, 1975;Flores et aL, 1980), but not in cell suspension cultures (Heimer and Filner, 1971;Mohanty and Fletcher, 1976;Beck and Renner, 1989), where it stimulates the production of that enzyme. This has been shown for Urtica (Ludwig, 1981;Renner, 1982) as well as for suspensioncultured cells of C. rubrum (Renner and Beck, 1988;Beck and Renner, 1989).…”

Section: A Molecular Biological Approach To the Action Of Cytokmentioning

confidence: 99%

The Morphogenic Response of Plants to Soil Nitrogen: Adaptive Regulation of Biomass Distribution and Nitrogen Metabolism by Phytohormones

Beck¹

1994

Flux Control in Biological Systems

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Ammonium repression of nitrate reductase formation in Lemna minor L.

Cited by 35 publications

References 23 publications

Patterns of nitrate reductase activity vary according to the plant functional group in a Mediterranean maquis

Patterns of nitrate reductase activity vary according to the plant functional group in a Mediterranean maquis

Influence of NO3 - and NH4 + nutrition on fermentation, nitrate reductase activity and adenylate energy charge of roots of Carex pseudocyperus L. and Carex sylvatica Huds. exposed to anaerobic nutrient solutions

The Morphogenic Response of Plants to Soil Nitrogen: Adaptive Regulation of Biomass Distribution and Nitrogen Metabolism by Phytohormones

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