Biochemical aspects of inorganic nitrogen assimilation by woody plants

Stewart, George R.; Pearson, Jennifer; Kershaw, Joanna L.; Clough, E.C.M.

doi:10.1051/forest:198905art0143

Cited by 27 publications

(11 citation statements)

References 11 publications

(20 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The similar preference of species for N-forms means that (all else being equal) the three Eucalyptus species are likely to compete for N. Results of this study contrast with those showing niche differentiation based on chemical forms of N (e.g. McKane et al, 2002;Miller and Bowman, 2003;Miller et al, 2007;Näsholm et al, 1998;Weigelt et al, 2003;, but are consistent with other studies showing that species preference for N-forms varies little among sympatric species (Kronzucker et al, 1997;Stewart et al, 1989). Based on the general absence of agreement among studies, the only conclusion that may be reached is that niche differentiation based on chemical forms of N occurs in some ecosystems but not all.…”

Section: Do Co-occurring Species Avoid Competing For N?contrasting

confidence: 57%

“…In contrast to these and other studies demonstrating niche differentiation (e.g. Miller and Bowman, 2003;Weigelt et al, 2003;, other studies have reported co-occurring species with similar preferences for N forms (Kronzucker et al, 1997;Stewart et al, 1989).…”

Section: Introductioncontrasting

confidence: 48%

“…Most studies showing similar patterns of N uptake among co-occurring species have estimated N uptake from hydrosolutions (e.g. this study, Kronzucker et al, 1997;Stewart et al, 1989), whereas most studies showing niche differentiation have estimated N uptake from injection of 15 N into the soil (e.g. McKane et al, 2002;Näsholm et al, 1998;Weigelt et al, 2005).…”

Section: Do Co-occurring Species Avoid Competing For N?mentioning

confidence: 97%

See 2 more Smart Citations

Competition for nitrogen by three sympatric species of Eucalyptus

2010

View full text Add to dashboard Cite

Abstract• Nitrogen (N) exists in the soil in a variety of different forms and thus plants may avoid competition by taking up N as different chemical forms.• This study examined the uptake of nitrate, ammonium and glycine by three co-occurring species of Eucalyptus (E. obliqua, E. radiata and E. rubida) from dry sclerophyll forest in south-eastern Australia. Species preference for N forms was determined by measuring uptake of glycine, nitrate and ammonium from 15 N-labelled solutions containing equimolar 100 μmol L −1 concentrations of all three N forms. KCl extracts were used to assess the relative abundance of the different forms of N in the soil's exchangeable pool.• KCl extracts of soil indicated that amino acids comprised 30-40% of the soluble non-protein N, while ammonium varied from 10-70% and nitrate from 5-70%. In all species, ammonium was the preferred source of nitrogen and was taken up 2.5-4.5 times faster than glycine, and 30-50 times faster than nitrate. Species did not differ in preference for N-forms (species*N-form interaction, not significant).• This study indicates that nitrate, ammonium and amino acids are all present in soil, and thus there is the potential for niche differentiation based on chemical forms of N. However, there is no evidence that co-occurring Eucalyptus avoid competition for N by taking up different chemical forms. Mots-clés :Eucalyptus / azote / absorption / acide aminé / compétition Résumé -Compétition pour l'azote par trois espèces d'Eucalyptus sympatriques.• L'azote (N) existe dans le sol sous une variété de formes différentes et donc les plantes peuvent éviter la concurrence en absorbant N depuis différentes formes chimiques.• Cette étude a porté sur l'assimilation du nitrate, de l'ammonium et de la glycine par trois espèces d'eucalyptus co-occurentes (E. obliqua, E. radiata et E. rubida) de la forêt sclérophylle sèche dans le sud-est de l'Australie. La préférence des espèces pour les formes de N a été déterminée en mesurant l'absorption de la glycine, du nitrate et de l'ammonium à partir de solutions marquées 15 N contenant des concentrations équimolaires de 100 μmol L −1 de toutes les trois formes de N. Des extraits de KCl ont été utilisés pour évaluer l'abondance relative des différentes formes de N dans le pool échangeable du sol.• Les extraits de KCl du sol ont indiqué que les acides aminés étaient constitués de 30-40 % de non protéines N solubles, tandis que l'ammonium variait de 10-70 % et les nitrates de 5-70 %. Chez toutes les espèces, l'ammonium était la source privilégiée d'azote et a été absorbé 2.5-4.5 fois plus vite que la glycine, et 30-50 fois plus vite que les nitrates. Les espèces ne diffèrent pas dans leur préférence pour les formes d'azote (interaction espèces*formes d'azote, non significative).• Cette étude indique que les nitrates, l'ammonium et les acides aminés sont tous présents dans le sol, et donc il y a le potentiel pour la différenciation de niches, basées sur des formes chimiques de N. Toutefois, il n'existe aucune preuve que les espèces co-...

show abstract

Section: Do Co-occurring Species Avoid Competing For N?contrasting

confidence: 57%

Section: Introductioncontrasting

confidence: 48%

Section: Do Co-occurring Species Avoid Competing For N?mentioning

confidence: 97%

See 1 more Smart Citation

Competition for nitrogen by three sympatric species of Eucalyptus

2010

View full text Add to dashboard Cite

show abstract

“…Nitrate reductase activities were lower in the leaves and roots of F. albida inoculated with the N # -fixing Bradyrhizobium strain ORS 188 than in plants fed mineral N. However, in both cases the shoot : root NR ratio was always 5. This type of NR partitioning is often observed in tropical and subtropical species including legumes such as Glycine max and Phaseolus vulgaris (Andrews, 1986) and woody species such as Ficus exasperata or Guierra senegalensis (Stewart et al, 1989). Wallace (1986) showed that herbaceous Phaseoleae of tropical origin carried out only 10% of their NO $ − reduction in roots and preferentially accumulated NO $ − in shoots.…”

Section: mentioning

confidence: 99%

“…Similarly, mineral N assimilation, and more especially the partitioning of NO $ − reduction and NH % + assimilation between shoots and roots, have not yet been defined for F. albida and Sahelian acacias. In woody plants, glutamine synthetase (GS, EC 1n6.3n2) is considered the key enzyme of NH % + assimilation (Stewart et al, 1989), as is nitrate reductase (NR, EC 1n6.6n1) for NO $ − assimilation (Miflin & Lea, 1980). It has been demonstrated that the glutamate synthase cycle (GS\GOGAT) accounted for most NH % + assimilation even if substantial glutamate dehydrogenase (GDH) activity is observed in, for example, roots and tissues under stress conditions (Smirnoff & Stewart, 1987 ;Srivastava & Singh, 1987).…”

Section: mentioning

confidence: 99%

Differences in nitrogen metabolism of Faidherbia albida and other N₂‐fixing tropical woody acacias reflect habitat water availability

Campa¹,

Diouf²,

Ndoye³

et al. 2000

New Phytologist

View full text Add to dashboard Cite

The activities of nitrate reductase and glutamine synthetase were evaluated in young plants of Faidherbia albida, a tropical woody legume, fed with different N sources under hydroponic conditions. Results showed that assimilation of both NO3− and NH4+ preferentially took place in shoots. A basal amount of nitrate reductase activity was detected in shoots of plants grown with an NO3−‐free solution or placed under N2‐fixing conditions, and also in nodules of N2‐fixing plants. This strongly suggests that constitutive nitrate reductase activity is present in these organs. Analyses of the soluble nitrogenous content showed that the major form of N in the different organs was α‐amino acids (particularly amides), irrespective of the N status of the culture conditions. The same result was obtained for nodulated plants grown in local sandy soil. In this case, amide‐N generally accounted for more than 40% of the total soluble N. This was especially true in nodules. Ureide‐N never exceeded 9% of the total soluble N and did not appear to increase with increasing nodule nitrogenase activity. Amides were also predominant in three N2‐fixing Sahelian acacias (Acacia seyal, A. nilotica and A. tortilis), showing that F. albida does not differ from Sahelian Acacia in terms of the metabolism of fixed N. However, like another Sahelian acacia growing preferentially near water (A. nilotica), F. albida can be distinguished from acacias growing strictly in arid zones (A. seyal and A. tortilis) in terms of initial growth, water and nitrate management.

show abstract

Does nitrogen concentration affect relative uptake rates of nitrate, ammonium, and glycine?

Warren

2009

Z. Pflanzenernähr. Bodenk.

View full text Add to dashboard Cite

Plant roots are exposed to a variety of nitrogen forms (e.g., nitrate, ammonium, amino acids) and take up these forms at different rates. Many studies have investigated whether plants prefer nitrate, ammonium, or amino acids; but studies may not be comparable because they used substrate concentrations between 100 and 2000 μmol L–1. This study tests the hypothesis that substrate concentrations from 10 to 1750 μmol L–1 affect plant preference for N forms. Nitrogen uptake by the herb Ocimum basilicum and the evergreen tree Eucalyptus regnans was examined by placing roots of intact seedlings in equimolar mixtures of nitrate, ammonium, and glycine in which one of the N forms was 15N‐labelled (and 13C‐labelled in the case of glycine). In both species, preference for N forms was affected by substrate concentration. At 10 μmol L–1 (O. basilicum) or 10 and 50 μmol L–1 (E. regnans), rates of N uptake did not differ among N forms. At substrate concentrations of 50 μmol L–1 and greater O. basilicum took up ammonium the fastest, glycine the slowest, and nitrate at an intermediate rate. At substrate concentrations from 100 to 1750 μmol L–1, E. regnans took up ammonium the fastest with glycine and nitrate taken up at slower rates. The absence of significant differences at lower concentrations was a true biological effect rather than a function of larger relative errors. This study demonstrates that substrate concentration has a large effect on plant preference for N forms, and sounds a warning for studies of N nutrition that do not consider the concentration‐dependence of plant preference for N forms.

show abstract

Biochemical aspects of inorganic nitrogen assimilation by woody plants

Cited by 27 publications

References 11 publications

Competition for nitrogen by three sympatric species of Eucalyptus

Competition for nitrogen by three sympatric species of Eucalyptus

Differences in nitrogen metabolism of Faidherbia albida and other N₂‐fixing tropical woody acacias reflect habitat water availability

Does nitrogen concentration affect relative uptake rates of nitrate, ammonium, and glycine?

Contact Info

Product

Resources

About

Biochemical aspects of inorganic nitrogen assimilation by woody plants

Cited by 27 publications

References 11 publications

Competition for nitrogen by three sympatric species of Eucalyptus

Competition for nitrogen by three sympatric species of Eucalyptus

Differences in nitrogen metabolism of Faidherbia albida and other N2‐fixing tropical woody acacias reflect habitat water availability

Does nitrogen concentration affect relative uptake rates of nitrate, ammonium, and glycine?

Contact Info

Product

Resources

About

Differences in nitrogen metabolism of Faidherbia albida and other N₂‐fixing tropical woody acacias reflect habitat water availability