Cupressus  dupreziana

A. Camus 1926 in Bull. Mus. Hist. Nat., Paris, 32(1) p.101.

Synonyms :
Cupressus sempervirens var. dupreziana (A. Camus) Silba 1981
Rejected : C. dupreziana, due to its reproduction characteristic (pollen is diploid, see: apomixis), does not hybridize with C. sempervirens.
Cupressus lereddei Gaussen 1950
Rejected : priority rule.

Common names :
Local nameFrançaisEnglish
TaroutCyprès du Tassili
Cyprès du Sahara		Saharan Cypress

Articles :
2005.
Christian Pichot, Mohamed El Maâtaoui, Benjamin Liens, Juana Laura Rivera Nava.
Unusual reproductive features in Mediterranean cypresses, and production of all paternal seedlings from a surrogate mother.
in The Paradox of Asexuality: An Evaluation. - An international joint European Science Foundation - Linnean Society meeting entitled PARTNER-4, Linnean Society, London, 22-24th September, 2005.
2003.
Richard B. Primack.
Genetic Piracy: A Newly Discovered Marvel of the Plant World.
Arnoldia 62-2.
2002.
Abdoun F, Beddiaf M.
Cupressus dupreziana A. Camus: distribution, decline and regeneration on the Tassili n'Ajjer, central Sahara.
C R Biol. 2002 May; 325(5):617-27. [Article in French]
  • As soon as it was first discovered in 1924, on the heights of the Tassili n'Ajjer, Cupressus dupreziana (A. Camus) was declared an endangered species. The few ancient trees to be seen in the beds of wadis gave reason to suppose that they were isolated individuals left behind from a forest that had flourished in a damper climate. Attempts at a census of the trees were made on a number of occasions, the fullest, in 1972, reporting a total of 230 living specimens. The revision of this inventory between 1997 and 2001 has now enabled us to draw the boundaries of the present range of this species, to assess its rate of decline over the last three decades and, for the first time, to record some regeneration, with the presence of new, young trees.
    2001.
    Pichot C., El Maâtaoui M., Raddi S., Raddi P.
    Surrogate mother for endangered Cupressus.
    Nature, 412:39.
  • A rare cypress tree increases its chances by using a clever reproductive strategy.
    2001.
    El Maâtaoui M, Pichot C.
    Microsporogenesis in the endangered species Cupressus dupreziana A. Camus: evidence for meiotic defects yielding unreduced and abortive pollen.
    Planta. 2001 Aug; 213(4):543-9.
  • To understand the reproductive biology of Cupressus dupreziana A. Camus (Cupressaceae), a highly endangered Mediterranean conifer, the processes of microsporogenesis and pollen differentiation were investigated cytologically. Pre-meiotic development proved to be similar to the coniferous pattern: the microsporangia differentiated sporogenous tissue in which microsporocytes separated and underwent meiosis. As the meiotic steps proceeded, unexpected irregularities were observed concerning chromosomal and nuclear behaviour. This mainly included: abnormal chromosome segregation and cytokinesis, and nuclear fusion of the meiotic products. The result was the formation, in the same microsporangium, of heterogeneous microspore populations arranged in monads, dyads, triads, tetrads, and polyads, and cytoplasts giving rise to pollen grains of different sizes. This indicates that in C. dupreziana both abortive and unreduced pollen grains are generated. The significance of the finding is discussed in relation to reproductive biology and vulnerability to extinction.
    2000.
    Pichot C., El Maâtaoui M.
    Unreduced diploid nuclei in Cupressus dupreziana A. Camus pollen.
    Theoretical and Applied Genetics, 101(4):574-579.
  • Abstract Size and DNA content of pollen of Cupressus dupreziana A. Camus, a highly endangered Mediterranean conifer, were assessed by cytomorphological observations and flow cytometric analyses and then compared to C. sempervirens L. pollen. Mature C. dupreziana pollen was composed of two uninucleated types of pollen grains differing in size. Around 35% of the grains exhibited a size similar to C. sempervirens pollen, while 65% exhibited a larger diameter. However only one peak of fluorescence was detected by flow cytometry. DNA content of C. dupreziana pollen was twice the DNA content of C. sempervirens pollen. Comparison of DNA contents of mature and germinating pollen revealed that mature pollen of both species were arrested in the G2 phase. Comparison with the DNA content of somatic tissue (2C) provided evidence for the production of unreduced pollen in C. dupreziana. This unexpected feature in gymnosperms is discussed in terms of reproductive strategy of this species.
    Keywords : 2n pollen - Cupressus dupreziana - Gymnosperms - Flow cytometry - Reproduction
    2000.
    Christian Pichot, Bruno Fady and Isabelle Hochu.
    Lack of mother tree alleles in zymograms of Cupressus dupreziana A. Camus embryos.
    Ann. For. Sci. 57 (2000) 17-22
    1998.
    C. Pichot, Agnès Borrut, Mohamed El Maâtaoui.
    Unexpected DNA content in the endosperm of Cupressus dupreziana A. Camus seeds and its implications in the reproductive process.
    Sexual Plant Reproduction, July 1998, 11(3):148-152
  • Abstract Nuclear DNA content of embryo and endosperm from mature and immature Cupressus dupreziana A. Camus seeds was estimated using laser flow cytometry. Relative DNA content of endosperm nuclei corresponded to four ploidy levels: 2C, 4C, 6C and 8C. The embryo nuclei invariably exhibited a diploid pattern. In all endosperm tissue analyzed no haploid nucleus was found. This is problematic since, in gymnosperms, endosperm and female gametes originate from one functional haploid megaspore produced by meiosis. The possible origin and derivation of C. dupreziana endosperm are discussed in light of previous results concerning the two other Mediterranean cypresses, C. sempervirens and C. atlantica.
    Keywords : Cupressus dupreziana - DNA content - Endosperm - Reproduction - Flow cytometry - Gymnosperm
    1995.
    Hoffmeisterová, R. - Dobrý, J.
    Will the Tassili population of Cupressus dupreziana survive?.
    In: Proceedings of the Eco-Conference on Africa, held in Prague. - (Ed. Daniel, M.). - Praha, Czech-African Society 1995. - S. 183-187.
    1989.
    Dobry, J. & J. Kyncl.
    Cupressus dupreziana - an endangered coniferous tree of the central Sahara.
    Lesnictvi 35(4):371-384.
    1988.
    Dobry, J.
    Cupressus dupreziana.
    Threatened Plants Newsletter 20:8. Expedition Tarout '81 reintroduction project.
    1984.
    Hrib, J. & Dobrý, J.
    An explant culture of Tassilian Cypress, Cupressus dupreziana.
    Forest Ecology and Management 8(3–4):235–24.
    1980.
    R. De Tarade.
    Cupressus dupreziana from Lebanon (cultivated).
    International Dendrology Society Yearbook 1979:97 (1980).