name = Diatoms

image_width = 200px
image_caption = Marine diatoms
domain = Eukaryota
regnum = Chromalveolata
phylum = Heterokontophyta
classis = Bacillariophyceae
ordo = Pennales

Order Pennales is a traditional subdivision of the heterokont algae known as diatomsHoek, C. van den, Mann, D. G. and Jahns, H. M. (1995). " [ Algae : An introduction to phycology] ", Cambridge University Press, UK.] Round, F. E. and Crawford, R. M. (1990). "The Diatoms. Biology and Morphology of the Genera", Cambridge University Press, UK.] . The order is named for the shape of the cell walls (or valves or frustules) of pennate diatoms, which are elongated in valve view. The valves may be linear or oval in shape, and usually bear bilaterally symmetrical ornamental patterns. These patterns are composed of a series of transverse lines (known as striae) that can appear as rows of dots when viewed with an optical microscope. Some pennate diatoms also exhibit a fissure along their longitudinal axis. This is known as a raphe, and is involved in gliding movements made by diatom cells; motile diatoms always possess a raphe.

In terms of cell cycle, vegetative cells are diploid and undergo mitosis during normal cell division. Periodically, meiosis produces morphologically-identical haploid gametes (isogametes), which fuse to produce a (sometimes binucleate) zygote that develops into an auxospore (from which full-size vegetative cells are produced).

In some taxonomic schemes, the pennate diatoms are divided into two groups: pennate diatoms without a raphe (Order Fragilariophyceae), and pennate diatoms with a raphe (Order Bacillariophyceae).

=See also=
* Centrales


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Look at other dictionaries:

  • Pennales — Saltar a navegación, búsqueda ? Pennales Diatomeas marinas …   Wikipedia Español

  • Pennales —   [lateinisch], Ordnung der Kieselalgen …   Universal-Lexikon

  • Pennales — Pennales, Ordnung der ⇒ Bacillariophyceae, die meist lateralsymmetrisch (stab , schiffchen , keilförmig) gebaute, vorwiegend die Böden von Süß und Salzwässern bewohnende, im Boden als Epiphyten auf Wasserpflanzen und manche auch als Plankter… …   Deutsch wörterbuch der biologie

  • Pennales Fechten — ist eine Sitte bei schlagenden Schülerverbindungen (Pennalkorporationen) vornehmlich in Österreich und in Deutschland. Dabei werden die Formen der studentischen Mensur des 19. Jahrhunderts nachgeahmt, jedoch mit dem leichten Säbel mit stumpfer… …   Deutsch Wikipedia

  • pennales — pen·na·les …   English syllables

  • pennales — pəˈnā(ˌ)lēz noun plural Usage: capitalized Etymology: New Latin, from Latin penna feather + New Latin ales : an order of diatoms having a raphe or pseudoraphe and ornamentation of the valves always bilaterally arranged in relation to a line… …   Useful english dictionary

  • Bacillariophyta — ou Diatomées …   Wikipédia en Français

  • Bacillariophytes — Bacillariophyta Bacillariophyta ou Diatomées …   Wikipédia en Français

  • Diatom — Bacillariophyta Bacillariophyta ou Diatomées …   Wikipédia en Français

  • Diatomée — Bacillariophyta Bacillariophyta ou Diatomées …   Wikipédia en Français

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