Alnus glutinosa

14,000,000 Leading Edge Experts on the ideXlab platform

Scan Science and Technology

Contact Leading Edge Experts & Companies

Scan Science and Technology

Contact Leading Edge Experts & Companies

The Experts below are selected from a list of 7359 Experts worldwide ranked by ideXlab platform

G. Pizelle - One of the best experts on this subject based on the ideXlab platform.

  • Nitrogenase and nitrate reductase activities in young Alnus glutinosa, relationship and effect of light/dark treatments
    Plant Physiology and Biochemistry, 1995
    Co-Authors: S. Benamar, G. Thiery, G. Pizelle
    Abstract:

    Relations between in vivo nitrogenase (N 2 -ase ; EC 1.18.6.1) and nitrate reductase (NR ; EC 1.6.6.1) activities were studied in young nodulated Alnus glutinosa (L.) Gaertn. Positive correlations linked N 2 -ase activity, constitutive (non-inducible by nitrate) leaf NR activity and plant growth. Light/dark treatments applied to the whole shoot or, separately, to the upper and lower part of shoot led to the finding that (a) the constitutive leaf NR activity depended on direct illumination of the leaf and did not appear subordinate to the N 2 -ase activity ; (b) the N 2 -ase activity was much more efficiently supported by the illumination of the upper (young) leaves than by that of the lower (mature) leaves ; (c) the maintenance of nitrate-inducible root NR activity required leaf illumination. The variations of both N 2 -ase and root NR activities in response to light/dark treatments emphasize the importance of the photosynthesis for the reduction of dinitrogen and nitrate in nodulated roots of Alnus glutinosa.

  • Relationship between nitrite and nitrate reductase activities in leaves of Alnus glutinosa and Robinia pseudoacacia
    Plant Physiology and Biochemistry, 1994
    Co-Authors: G. Pizelle, G. Thiery
    Abstract:

    In vivo and in vitro methods were devised to investigate the nitrite reductase (EC 1.7.7.1) (NiR) activity of leaves of Alnus glutinosa and Robinia pseudoacacia, its relations with light, photosynthetic inhibitors and nitrate supply, and its seasonal variations compared with those of the nitrate reductase (EC 1.6.6.1) (NR) activity. In both species, NiR activity was found in leaves of young plants dependent upon symbiotic nitrogen fixation, as well as in field leaves; moreover, its level was not increased by nitrate supply to excised leaves, thereby implying its constitutive nature. NR and NiR activities were present in the field leaves from the bud break to the autumn

G. Thiery - One of the best experts on this subject based on the ideXlab platform.

  • Nitrogenase and nitrate reductase activities in young Alnus glutinosa, relationship and effect of light/dark treatments
    Plant Physiology and Biochemistry, 1995
    Co-Authors: S. Benamar, G. Thiery, G. Pizelle
    Abstract:

    Relations between in vivo nitrogenase (N 2 -ase ; EC 1.18.6.1) and nitrate reductase (NR ; EC 1.6.6.1) activities were studied in young nodulated Alnus glutinosa (L.) Gaertn. Positive correlations linked N 2 -ase activity, constitutive (non-inducible by nitrate) leaf NR activity and plant growth. Light/dark treatments applied to the whole shoot or, separately, to the upper and lower part of shoot led to the finding that (a) the constitutive leaf NR activity depended on direct illumination of the leaf and did not appear subordinate to the N 2 -ase activity ; (b) the N 2 -ase activity was much more efficiently supported by the illumination of the upper (young) leaves than by that of the lower (mature) leaves ; (c) the maintenance of nitrate-inducible root NR activity required leaf illumination. The variations of both N 2 -ase and root NR activities in response to light/dark treatments emphasize the importance of the photosynthesis for the reduction of dinitrogen and nitrate in nodulated roots of Alnus glutinosa.

  • Relationship between nitrite and nitrate reductase activities in leaves of Alnus glutinosa and Robinia pseudoacacia
    Plant Physiology and Biochemistry, 1994
    Co-Authors: G. Pizelle, G. Thiery
    Abstract:

    In vivo and in vitro methods were devised to investigate the nitrite reductase (EC 1.7.7.1) (NiR) activity of leaves of Alnus glutinosa and Robinia pseudoacacia, its relations with light, photosynthetic inhibitors and nitrate supply, and its seasonal variations compared with those of the nitrate reductase (EC 1.6.6.1) (NR) activity. In both species, NiR activity was found in leaves of young plants dependent upon symbiotic nitrogen fixation, as well as in field leaves; moreover, its level was not increased by nitrate supply to excised leaves, thereby implying its constitutive nature. NR and NiR activities were present in the field leaves from the bud break to the autumn

Torgny Unestam - One of the best experts on this subject based on the ideXlab platform.

  • comparative studies of ectomycorrhiza formation in Alnus glutinosa and pinus resinosa with paxillus involutus
    Mycorrhiza, 1999
    Co-Authors: Hugues B Massicotte, Lewis Melville, R L Peterson, Torgny Unestam
    Abstract:

    Mycorrhiza ontogeny and details of Hartig net and mantle structure were compared in ectomycorrhizas synthesized in growth pouches between the broad host range fungus Paxillus involutus and the tree species European black alder (Alnus glutinosa) and red pine (Pinus resinosa). In Alnus glutinosa, a paraepidermal Hartig net was restricted to the proximal (basal) portion of first-order laterals; the hypodermal layer appeared to be a barrier to fungal penetration. Phi-thickenings were present in some cortical cells but these were not related to lack of fungal ingress into the cortex. The mantle was often present close to the root apex but in many roots it was loosely organized and patchy. In several instances, the mantle formed around the root apex was only temporary; renewed root growth occurred without the formation of a mantle. In Pinus resinosa, the Hartig net developed between cortical cell layers of monopodial and dichotomously branched first–order laterals. Fungal hyphae in the Hartig net exhibited a complex labyrinthine mode of growth. The mantle had a pseudoparenchymatous structure and covered the root, including apices of dichotomously branched roots. The Paxillus–Pinus resinosa interaction had all the characteristics of a compatible ectomycorrhizal association. The Paxillus–Alnus glutinosa interaction, however, showed only aspects of superficial ectomycorrhizas, including the presence of a minimal (sometimes absent) and mostly proximal Hartig net and variable mantle development. Sclerotia were produced in the extraradical mycelium of Paxillus involutus when associated with either Alnus glutinosa or Pinus resinosa.

Nedim Saraçoğlu - One of the best experts on this subject based on the ideXlab platform.

A.d.l. Akkermans - One of the best experts on this subject based on the ideXlab platform.

  • Ineffective Frankia strains in wet stands of Alnus glutinosa (L.) Gaertn. in the Netherlands.
    Soil Biology and Biochemistry, 1997
    Co-Authors: D.j. Wolters, A.d.l. Akkermans, C. Van Dijk
    Abstract:

    Nodulation experiments using Alnus glutinosa L. Gaertn. (black alder) seedlings as hosts and soil suspensions as inoculants were made to determine the presence and relative amounts of ineffective (non-nitrogen fixing but infectious) Frankia strains in 10 waterlogged soils of natural alder stands in the Netherlands. Ineffective nodules were formed with soil from six locations, while effective nodules were found at all sites. From three of these locations the majority of the nodules formed were of the ineffective type. These results suggested that ineffective strains form an important fraction of the Frankia population of wet soils under black alder vegetation. No correlation (r(2), P

  • ag13 is expressed in Alnus glutinosa nodules in infected cells during endosymbiont degradation and in the nodule pericycle
    Physiologia Plantarum, 1997
    Co-Authors: C. Guan, A.d.l. Akkermans, Van Kammen, Ton Bisseling, Katharina Pawlowski
    Abstract:

    We isolated and characterized an Alnus glutinosa cDNA clone, pAg13, which corresponds to a gene expressed at higher levels in nodules induced by Frankia than in roots. The deduced polypeptide sequence is rich in glutamic acid and proline and contains a putative signal peptide indicating an extracellular location of Ag13. In situ hybridization showed that ag13 is expressed in the pericycle of the nodule vascular bundle and in infected cells that exhibited degradation of the endosymbiont.

  • Phylogenetic characterization of ineffective Frankia in Alnus glutinosa (L.) Gaertn. nodules from wetland soil inoculants
    Molecular ecology, 1997
    Co-Authors: D.j. Wolters, C. Van Dijk, E. G. Zoetendal, A.d.l. Akkermans
    Abstract:

    Ineffective Frankia endophytes were retrieved from various wet soils by using Alnus glutinosa clones as trapping plants. No pure cultures could be isolated from these ineffective nodules. Therefore, the phylogenetic position of these endophytes was determined by sequence analysis of cloned PCR products of bacterial 16S rDNA, derived from nodules. The results showed that all nodule endophytes belong to a hitherto undescribed cluster of the Frankia phylogenetic tree. The position of these uncultured ineffective Frankia nodule endophytes is different from that of the ineffective Frankia isolates derived from A. glutinosa nodules, even when originating from the same geographical location. This suggests a bias in current isolation techniques.

  • Gene expression in ineffective actinorhizal nodules of Alnus glutinosa.
    Acta Botanica Gallica, 1996
    Co-Authors: C. Guan, A.d.l. Akkermans, D.j. Wolters, C. Van Dijk, A. Van Kammen, T. Bisseling, Katharina Pawlowski
    Abstract:

    Summary Several Frankia strains have been shown to induce ineffective, i.e. non-nitrogen fixing nodules, sometimes in a host-plant dependent manner. Previous studies have demonstrated that the resistance to nodulation of Alnus glutinosa by ineffective Frankia strains is genetically determined. In this study, ineffective nodules induced on susceptible Alnus glutinosa clones by soil suspensions from a local swamp were analysed cytologically. Comparisons with effective nodules showed that ineffective nodules contain higher amounts of polyphenols than effective nodules, indicating a plant defense reaction. Polyphenols were found even in the infected cortical cells. In situ hybridization with a Frankia antisense 16S rRNA probe showed that Frankia is degraded at an early stage of development of infected cells. The mRNAs of two plant genes, ag12ar\6 ag13, which had been found to be expressed in the infected cells of effective nodules, were localized in ineffective nodules. Their expression patterns seemed to be ...

  • Nitrogen metabolism in actinorhizal nodules of Alnus glutinosa: expression of glutamine synthetase and acetylornithine transaminase
    Plant molecular biology, 1996
    Co-Authors: C. Guan, A.d.l. Akkermans, A. Van Kammen, T. Bisseling, Ana Ribeiro, Y. Jing, Katharina Pawlowski
    Abstract:

    Two nodule cDNA clones representing genes involved in Alnus glutinosa nitrogen metabolism were analysed. ag11 encoded glutamine synthetase (GS), the enzyme responsible for ammonium assimilation, while ag118 encoded acetylornithine transaminase (AOTA), an enzyme involved in the biosynthesis of citrulline, the nitrogen transport form in Alnus. GS mRNA was found at highest levels in root nodules, where it was present in the infected cells as well as in the cells of the pericycle of the vascular system. AOTA transcripts were found at high levels in nodules, confined to the infected cells, suggesting that in nodules of A. glutinosa, citrulline biosynthesis takes place mainly in the infected cells.

Related terms

Alnus glutinosa - 15 days free trial to Access Experts & Abstracts