Effect of Nitrate and Ammonium Nutrition of Nonnodulated <i>Phaseolus vulgaris</i> L. on Phosphoenolpyruvate Carboxylase and Pyruvate Kinase Activity

Schweizer, Patrick; Erismann, Karl Hans

doi:10.1104/pp.78.3.455

Cited by 51 publications

(42 citation statements)

References 17 publications

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“…This indicates that NRA probably responded to induction of NR expression by NO 3 -, rather than to post-translational regulation, and that changes in NRA activity induced by varying root-zone CO 2 concentrations (Cramer et al, 1996) probably depend on NO 3 -uptake. Phosphoenolpyruvate carboxylation may serve as a source of anaplerotic C during NH 4 + assimilation to compensate for the loss of TCA cycle intermediates to amino acid synthesis or as a source of C for organic acid synthesis in NO 3 --fed plants to maintain ionic balance in the xylem sap (Schweizer & Erismann, 1985;Vuorinen & Kaiser, 1997 (Fig. 2), possibly as a consequence of feedback inhibition.…”

Section: Discussionmentioning

confidence: 99%

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The influence of root assimilated inorganic carbon on nitrogen acquisition/assimilation and carbon partitioning

Viktor

Cramer

2004

New Phytologist

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Summary• Understanding of the influences of root-zone CO 2 concentration on nitrogen (N) metabolism is limited.• The influences of root-zone CO 2 concentration on growth, N uptake, N metabolism and the partitioning of root assimilated 14 C were determined in tomato ( Lycopersicon esculentum ).• Root, but not leaf, nitrate reductase activity was increased in plants supplied with increased root-zone CO 2 . Root phosphoenolpyruvate carboxylase activity was lower with NO 3 --than with NH 4 + -nutrition, and in the latter, was also suppressed by increased root-zone CO 2 . Increased growth rate in NO 3 --fed plants with elevated root-zone CO 2 concentrations was associated with transfer of root-derived organic acids to the shoot and conversion to carbohydrates. With NH 4 + -fed plants, growth and total N were not altered by elevated root-zone CO 2 concentrations, although 14 C partitioning to amino acid synthesis was increased.• Effects of root-zone CO 2 concentration on N uptake and metabolism over longer periods (> 1 d) were probably limited by feedback inhibition. Root-derived organic acids contributed to the carbon budget of the leaves through decarboxylation of the organic acids and photosynthetic refixation of released CO 2 .

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Section: Discussionmentioning

confidence: 99%

“…Incorporation of DIC enables synthesis of organic acids, which may in turn be utilized for amino acid synthesis (Schweizer & Erismann, 1985;Ikeda et al ., 1992;Vuorinen & Kaiser, 1997), exudation (e.g. for chelation of aluminium (Al); Cramer & Titus, 2001) and other processes dependant on organic acids.…”

Section: Introductionmentioning

confidence: 99%

The influence of root assimilated inorganic carbon on nitrogen acquisition/assimilation and carbon partitioning

Viktor

Cramer

2004

New Phytologist

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“…Phosphoenolpyruvate carboxylase (PEPc), catalysing the synthesis of oxaloacetate from PEP and HCO $ − , is a ubiquitous enzyme in plants that might function in the anaplerotic replenishment of tricarboxylic acid cycle intermediates, NAD(P)H generation, refixation of respiratory CO # (Vuorinen & Kaiser, 1997), as a pH-stat or for the provision of carboxylates to maintain ionic balance in the xylem sap (Schweizer & Erismann, 1985 ;Arnozis et al, 1988). Spontaneous pH-dependent interconversion of CO # and HCO $ − is slow, and carbonic anhydrase is required to catalyse the reaction (Hatch & Burnell, 1990 ;Raven & Newman, 1994).…”

Section: mentioning

confidence: 99%

The influence of dissolved inorganic carbon in the rhizosphere on carbon and nitrogen metabolism in salinity‐treated tomato plants

1999

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The influence of variation in the concentration of dissolved inorganic carbon (DIC) in the form of CO # and HCO $ − in the root media on the C and N metabolism of Lycopersicon esculentum cv. F144 was investigated under both saline and non-saline conditions. Tomato seedlings were grown in hydroponic culture (pH 6.5) with or without NaCl, and the root solution was aerated with either ambient CO # (360 µmol mol −" ) or CO # -enriched air (5000 µmol mol −" ). Nitrate uptake and root tissue NO $ − concentrations were increased slightly by elevated rhizosphere DIC concentrations in both control and salinity-treated plants. This was associated with 46% higher nitrate reductase activity in the roots of control plants supplied with elevated DIC than in those supplied with ambient DIC. The activity of phosphoenolpyruvate carboxylase (PEPc) in vitro in control and salinity-treated plants was unaffected by the supply of elevated rhizosphere DIC concentrations. However, PEPc activity in vitro was considerably higher than the rates of PEPc activity in vivo reported previously, indicating that PEPc activity was not in itself a limitation on the provision of anaplerotic C. Therefore elevated DIC concentration in the rhizosphere stimulated the uptake of NO $ − and provided alternative C skeletons for the assimilation of the NH % + resulting from NO $ − reduction into amino acids within the roots. Salinity stimulated root glutamine synthetase (GS) activity up to double that in control plants. Furthermore, elevated DIC caused an increase in leaf and root GS activity of control plants while inhibiting GS activity in the roots of salinity-treated plants. Glutamine : 2-oxoglutarate aminotransferase (GOGAT) activity of salinity-treated plants was doubled by elevated rhizosphere DIC concentrations. These changes in GS and GOGAT activity must reflect changes in amino acid synthesis. Under saline conditions the xylem transport of NO $ − is partly blocked and a larger root assimilation develops, requiring not only the transamination of 2-oxoglutarate to glutamate but also that of oxaloacetate to aspartate and the transamidation of aspartate to asparagine.

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“…The synthesis of 2-oxoglutarate (2-OG) which is required for the assimilation of nitrate is based on the activity of phosphoenolpyruvate carboxylase (PEPcase), which is higher under NO À 3 compared to NH 4 supply (Schweitzer and Erismann, 1985;Kandlbinder et al, 1997). This higher PEPcase activity should affect the cytosolic CO 2 concentration and mitochondrial activity and, thus, the CO 2 compensation point (Häusler et al, 1999).…”

Section: Introductionmentioning

confidence: 99%

Influence of N form on growth photosynthesis of Phaseolus vulgaris L. plants

Brück

Guo

2006

Z. Pflanzenernähr. Bodenk.

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SummaryMany plant species are characterized by pronounced sensitivity to sole ammonium supply and exhibit growth depression and particularly reduced leaf growth rates. Stress symptoms under sole ammonium supply may be related to perturbation of photosynthetic processes, e.g., low rates of net CO 2 assimilation, low quantum yield, reduced stomatal conductance, and carboxylation capacity. The results of three experiments with French bean plants supplied with an N concentration of 5 mM illustrate significantly lower dry mass and specific leaf area, reduced leaf expansion, and higher chlorophyll and N content of ammonium-compared to nitrate-supplied plants. Light-saturated rates of CO 2 assimilation (A max ) per unit leaf area were higher under ammonium compared to nitrate supply while no significant effects of N form on quantum yield and A max per unit leaf weight and chlorophyll were found. Maximal carboxylation (V cmax ) and electron-transport (J Max ) rates were significantly higher under ammonium supply only in one of three experiments. V cmax was linearly related to total leaf N, the slope of the regression was similar with both N forms, the x-axis intercept was significantly higher for ammonium-compared to nitrate-supplied plants. The ratio V cmax : J Max was not affected by N form. It is concluded that ammonium supply had no negative effects on the operation of photosynthetic protein-enzyme complexes.

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Effect of Nitrate and Ammonium Nutrition of Nonnodulated Phaseolus vulgaris L. on Phosphoenolpyruvate Carboxylase and Pyruvate Kinase Activity

Cited by 51 publications

References 17 publications

The influence of root assimilated inorganic carbon on nitrogen acquisition/assimilation and carbon partitioning

The influence of root assimilated inorganic carbon on nitrogen acquisition/assimilation and carbon partitioning

The influence of dissolved inorganic carbon in the rhizosphere on carbon and nitrogen metabolism in salinity‐treated tomato plants

Influence of N form on growth photosynthesis of Phaseolus vulgaris L. plants

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