Arlette Nougarède

Arlette Nougarède, wife Lance, born in 1930 in Narbonne, is a cell biologist specializing in plant development from embryogenesis to flowering. She was Professor Emeritus at Pierre and Marie Curie University from 1992 to 2013. She has been a corresponding member of the French Academy of sciences since 1987.[1][2]

Biography

After her graduate studies in Paris, she obtained, at the École Normale Supérieure (ENS, 1952), a DES, prepared under the direction of Professor Roger Buvat. She began her career at the CNRS (1953), passed her State thesis (February 1958) and became a supervisor at the ENS (1960), preparing for the agrégation, recruited her first thesis students and then became Professor (1964) at the University Pierre et Marie Curie, Paris, where she developed her laboratory of Experimental Cytology and Plant Morphogenesis (CEMV), directed the DEA of the same name and integrated new thesis students and numerous trainees. Arlette Nougarède taught in all cycles until 1992 when she ended her career as Professor Emeritus, exceptional class 2.

The CEMV laboratory has regularly welcomed renowned foreign Professors: G. Bernier (Belgium), E.M. Gifford (USA), P.E. Pilet (Switzerland), C. Sterling (USA), S. Tepfer (USA), D. Francis (England), N. Bagni (Italy), who have come for collaborative work or to adapt to their equipment the new technologies developed in the team.

After her retirement, Arlette Nougarède continues her activities in the laboratory of Professor Dominique Chriqui (proofreading of theses, critical review of articles, participation in various juries and commissions, including the Neology and Terminology Commission of the French Academy of sciences).

Scientific Works

Arlette Nougarède's research focuses on the primary meristems of higher plants (structural and ultrastructural cytology; cytochemistry, DNA, RNA, proteins; functioning, cell cycle).

Caulinary meristem

After simple mitosis surveys for the vegetative point of Bean,[3] quantitative methods are gradually being used to estimate mean cell, nuclear, nucleolar volumes and to evaluate mitotic and labelling indices, after incorporation, by the meristem, of tritiated precursors of DNA and RNA synthesis.[4][5] For vegetative caulinary meristem, the notion of 3-component zonation is defended (axial apical zone, reserved territory, lateral leaf initiating zone, medullary meristem giving the pith), defined on cytological[6] [7] and functional criteria.[8][9] The total duration of the cell cycle, in hours, and that of its phases (G1,S,G2,M) show that the axial apical zone has the longest cycle, the lateral zone the shortest cycle and the medullary meristem a cycle of intermediate duration. In this cycle, the duration of mitosis, M, is not very variable, depending on the zone, and the same is true for synthesis, S, and postsynthesis, G2. Only the presynthesis phase G1, by its lengthening in the axial zone, its shortening in the lateral zone and, to a lesser degree, in the medullary meristem, ensures the control of proliferation in the vegetative meristem.

Phases of development

There is evidence that the meristem of preferred or strict photoperiodic plants, constantly subjected to light conditions unfavourable to their flowering, evolves towards a new phase: the intermediate phase[9] which is a preparation for flowering for preferred plants with increased yield, an ontogenic dead end for strict plants if favourable light conditions are not received. The following pre-flowering phase[9] is characterized by the reactivation of the axial apical zone, the cessation of foliar initiation and the rapid differentiation of the cells of the medullary meristem. The quantitative and/or qualitative changes in polypeptides and the time at which they occur are specified for each of the phases of development[10] and during initiation of the floral organs.[11]

The cell cycle is stopped at G1 in the meristem of dormant buds,[12][13] in that of the embryo contained in the seed[14] or in the cotyledonary bud of the fully inhibited Pea. Arlette Nougarède shows, on the Pea model, that there is an increasing gradient of inhibition from the buds located in the axils of the youngest leaves to the cotyledonal bud; the events related to the reactivation of the buds are examined.[15][16]

Root meristem. Geotropic reaction, Lentil, Corn

The very first data on the mechanism of the geotropic reaction are acquired - after experiments on starch lysis[17] of statenchyma amyloplasts and - microsurgery of the cuff and meristem. It has been proven that the cap amyloplasts are the geoperceptors and that the curvature of the root, placed in a horizontal position, is achieved in the zone of maximum elongation by growth asymmetry on both sides of the root under the control of an inhibitor from the cap.[18]

Rhizogenesis

Arlette Nougarède and her team identify, in the whole plant, regions of constant localization, differentiated into G1 and which possess organogenic capacities that neighbouring cells, which have become polyploid, have lost. Various types of rhizogenesis are compared (natural,[19] auxin-induced or Agrobacterium rhizogenes[20]).

Each era has its achievements. In the 20th century, histocytology and ontogenic examination made it possible to understand how plant meristems regularly form cells that differentiate into organ building tissues. These are indisputable data.[21] In the 21st century, molecular biology and mutants are bringing new ideas that will be able to solve[22] still unanswered problems.

Honours and Awards

Prizes
  • 1965: Ernest Dechelle Prize of the French Academy of sciences
  • 1976: Paul Doistau - Emile Blutel Prize of the French Academy of sciences
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References
  1. "Arlette Nougarède". Académie des sciences (in French). Retrieved 19 March 2019.
  2. Véronique Helft-Malz et Paule-Henriette Lévy, Les femmes dans la société française, Paris, Patrick Banon, 1997, 246 p. ISBN 978-2-84192-038-9, notice BnF no FRBNF36167392, lire en ligne)
  3. A. Lance, « Sur la structure et le fonctionnement du point végétatif de Vicia faba L. », Ann. Sci. Nat. Bot., 1952, 11è série, p. 301-339
  4. A. Nougarède, « Sur l'incorporation de l'adénine marquée au tritium (3H) dans les noyaux et le cytoplasme des cellules de deux méristèmes caulinaires : Lupinus albus (Papilionacées) et Teucrium scorodonia (Labiées) », C. R. Acad. Sc., 1961, 252, p. 1504-1506A.
  5. A. Nougarède et R. Bronchart, « Description des lieux d'incorporation de la thymidine tritiée au niveau des infrastructures du méristème préfloral du Perilla nankinensis (Lour.) Decne », C. R. Acad. Sc., 1967, 264, p. 1844-1847
  6. A. Lance, « Recherches cytologiques sur l'évolution de quelques méristèmes apicaux et sur ses variations provoquées par des traitements photopériodiques », Ann. Sci. Nat. Bot., IIè série, 1957, 18, p. 91-421
  7. A. Nougarède, « Experimental cytology of the shoot apical cells during vegetative growth and flowering », Intern. Rev. of Cytology, 1967, 21, p. 203-351
  8. A. Nougarède, « Méristèmes », Encyclopaedia Universalis, 1985, vol. 11, p. 1119-1133
  9. A. Nougarède, « Chrysanthemum segetum L. In Handbook of flowering, », Halevy A. H., éd. CRC Press, Boca Raton, Fla, 1985, vol. vi, p. 196-227
  10. J. Rembur et A. Nougarède, « Changes in the polypeptidic composition during the ontogenic development of the shoot apex of Chrysanthemum segetum analysed by two-dimensional mini-gel electrophoresis », Plant Cell Physiol., 1989, 30, p. 359-363
  11. D. Francis, J. Rembur et A. Nougarède, « Resolution of polypeptides in the shoot apex of Silene using 2D minigel electrophoresis: a feasibility study », Society for Experimental Biology, Lancaster Univ Avril, 1988
  12. S.S. Tepfer, A. Nougarède et P. Rondet, « Seasonal studies of vegetative buds of Helianthus tuberosus : concentration of nuclei in phase G1 during winter dormancy », Can. J. Bot, 1981, 59, p. 1918-1927
  13. E. Silveira, P. Rondet et A. Nougarède, « In nature dormant buds and in vitro dormant-like buds of Fraximus excelsior L. », Proto-plasmas, 1996, 190, p. 16-24
  14. E. Schatt, P. Landre et A. Nougarède, « Etat nucléaire des méristèmes du pois dans la graine sèche ; imbibition et reprise du cycle cellulaire », Can. J. Bot., 1985, 63, p. 2200-2208
  15. A. Nougarède et P. Rondet, « Evolution des index mitotiques et des teneurs de DNA nucléaire dans le méristème axillaire de la feuille de rang 6, lors de la levée de dominance apicale provoquée par ablation de l'axe principal, chez le Pisum sativum L. », C. R. Acad. Sc., 1975, 280, p. 973-976
  16. A. Nougarède, P. Rondet et J. Rembur, « Effets comparés de la fusicoccine, de la kinétine et de l'ablation de l'axe principal sur le bourgeon cotylédonnaire inhibé du Pois nain », Can. J. Bot, 1982, 60, p. 210-216
  17. A. Nougarède et P.E. Pilet, «  Action de l'acide gibbérellique GA3 sur l'ultrastructure des amyloplastes du statenchyme de la racine du Lens culinaris L», C. R. Acad. Sc, 1971, 273, p. 864-867
  18. A. Nougarède et P.E. Pilet, « Inhibiteur racinaire et zone de courbure de segments verticaux du Lens culinaris et du Zea mays L. », C. R. Acad. Sc, 1974, 279, p. 477-480
  19. A. Nougarède et P. Rondet, « Rhizogenèse adventive dans l'épicotyle du Pois : Initiation et structuration de la racine », Can. J. Bot., 1982, 60, p. 210-218
  20. J. Bercetche, D. Chriqui et A. Nougarède, « Comparison between induced rhizogenesis by auxins and Agrobacterium rhizogenes in Pisum sativum », Acta universitatis agriculturae, Brno,, 1985, 33, p. 423-427
  21. R. Buvat, Ontogeny, cell differentiation, and structure of vascular plants, Berlin, Heidelberg, New York, London, Paris, Tokyo, Springer Verlag, 1989, 581 p.
  22. A. Nougarède, « Le méristème caulinaire des Angiospermes : nouveaux outils, nouvelles interprétations », Acta Bot. Gallica, 2001,148 (1), p. 3-77
  23. "Des femmes à l'honneur". Femmes ingénieure.fr (in French). 2 January 2014. Retrieved 19 March 2019.
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