Structure of corystospermaceous ovules from the Upper Triassic of Zimbabwe

Barale, Georges; Guignard, Ga�tan; Bamford, Marion K.
September 2009
Botany;Sep2009, Vol. 87 Issue 9, p854
Academic Journal
Isolated ovules from the Upper Triassic of Zimbabwe were observed using three complementary approaches: light microscopy and, for the first time, scanning electron microscopy and transmission electron microscopy. Complete ovules showed a curved bifid micropylar tube. Three envelopes were present: integument, nucellus, and megaspore. The integument appeared resiniferous. The nucellus was made up of bulging cells around the pollen chamber, which contained bisaccate pollen grains. The ultrastructure of the nucellus revealed a lamellar organization in their microsinuosities. The megaspore membrane was made up of agglomerate rounded bodies more or less closely arranged and surrounded by two layers. The material may be attributed to Umkomasiaceae. A comparison with ovules of different related groups (seed ferns, Caytoniales, Ginkgoales, Nilssoniales, and Coniferales) was made. The Umkomasiales are considered to be a more primitive group than the Pteridospermales with regard to integument and nucellus.


Related Articles

  • Molecular and ultrastructural analysis of forisome subunits reveals the principles of forisome assembly. Müller, Boje; Groscurth, Sira; Menzel, Matthias; Rüping, Boris A.; Twyman, Richard M.; Prüfer, Dirk; Noll, Gundula A. // Annals of Botany;Jun2014, Vol. 113 Issue 7, p1121 

    Background and Aims Forisomes are specialized structural phloem proteins that mediate sieve element occlusion after wounding exclusively in papilionoid legumes, but most studies of forisome structure and function have focused on the Old World clade rather than the early lineages. A comprehensive...

  • Comparative anatomy of the nectary spur in selected species of Aeridinae (Orchidaceae). Stpiczyńska, Małgorzata; Davies, Kevin L.; Kamińska, Magdalena // Annals of Botany;Mar2011, Vol. 107 Issue 3, p327 

    Background and Aims To date, the structure of the nectary spur of Aeridinae has not been studied in detail, and data relating to the nectaries of ornithophilous orchids remain scarce. The present paper compares the structural organization of the floral nectary in a range of Aeridinae species,...

  • Comparative anatomy of floral elaiophores in Vitekorchis Romowicz & Szlach., Cyrtochilum Kunth and a florally dimorphic species of Oncidium Sw. (Orchidaceae: Oncidiinae). Davies, Kevin L.; Stpiczyńska, Małgorzata; Rawski, Michał // Annals of Botany;Jun2014, Vol. 113 Issue 7, p1155 

    Background and Aims Recently, molecular approaches have been used to investigate the phylogeny of subtribe Oncidiinae, resulting in the re-alignment of several of its genera. Here, a description is given of the structure of the floral elaiophores (oil glands) of four species formerly assigned to...

  • Vibrational Spectroscopy in Electron Microscopy: New Capabilities at SuperSTEM. Nellist, Peter D. // LabAsia;Mar/Apr2015, Vol. 22 Issue 2, p48 

    The article explains the importance of developments in the field of scanning transmission electron microscopy (STEM), how the SuperSTEM Laboratory in Daresbury, England came about and the instrument it launched.

  • Scanning and transmission electron-microscopic study of the development of the podocyte in the human fetus. Hyodo, Toru; Naguro, Tomonori; Kameie, Toshio; Iino, Akihiro; Miyagawa, Ikuo // Pediatric Nephrology;1997, Vol. 11 Issue 2, p133 

    The metanephric kidneys of seven human fetuses at 11-17 weeks' gestation were examined by scanning and transmission electron microscopy in order to evaluate differentiation of glomerular podocytes. When glomeruli were in the stage of S-shaped bodies, the surface of the visceral epithelium of...

  • Prevention of micropipes and voids at β-SiC/Si(100) interfaces. Scholz, R.; Gösele, U.; Wischmeyer, F.; Niemann, E. // Applied Physics A: Materials Science & Processing;1998, Vol. 66 Issue 1, p59 

    Abstract. Chemical vapor deposition (CVD) carbonization experiments were carried out on (100) silicon substrates. Scanning and transmission electron microscopy (SEM and TEM) were used to detect and characterize the interlace defects. Conditions for preventing the formation of micropipes and...

  • Large-scale synthesis of SnO[sub 2] nanobelts. Sun, S.H.; Meng, G.W.; Wang, Y.W.; Gao, T.; Zhang, M.G.; Tian, Y.T.; Peng, X.S.; Zhang, L.D. // Applied Physics A: Materials Science & Processing;2003, Vol. 76 Issue 2, p287 

    Tin dioxide (SnO[sub 2] ) nanobelts have been successfully synthesized in bulk quantity by a simple and low-cost process based on the thermal evaporation of tin powders at 800 �C. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) observations reveal that the...

  • Transmission and scanning electron microscopy studies of single femtosecond- laser-pulse ablation of silicon. Borowiec, A.; MacKenzie, M.; Weatherly, G.C.; Haugen, H.K. // Applied Physics A: Materials Science & Processing;2003, Vol. 76 Issue 2, p201 

    The final state of the material resulting from laser irradiation of silicon using 130 fs pulses at 790 nm was studied using a number of techniques including scanning and transmission electron microscopies, as well as atomic force microscopy. Structural details and the level of damage to the...

  • Synthesis, characterization and magnetic properties of Co3O4 nanotubes. Xiao-Ping Shen; Hua-Juan Miao; Hui Zhao; Zheng Xu // Applied Physics A: Materials Science & Processing;Apr2008, Vol. 91 Issue 1, p47 

    Well-aligned Co3O4 nanotubes were synthesized within the nanochannels of porous anodic alumina membranes using a single-source chemical vapor deposition method. Scanning electron microscopy and transmission electron microscopy showed that the Co3O4 nanotubes are highly ordered with uniform...


Read the Article


Sorry, but this item is not currently available from your library.

Try another library?
Sign out of this library

Other Topics