Communicating editor: K. Okuda.
Auxosporulation of Licmophora communis (Bacillariophyta) and a review of mating systems and sexual reproduction in araphid pennate diatoms
Article first published online: 22 FEB 2006
Volume 52, Issue 1, pages 1–12, March 2004
How to Cite
Chepurnov, V. A. and Mann, D. G. (2004), Auxosporulation of Licmophora communis (Bacillariophyta) and a review of mating systems and sexual reproduction in araphid pennate diatoms. Phycological Research, 52: 1–12. doi: 10.1111/j.1440-1835.2003.00319.x
- Issue published online: 22 FEB 2006
- Article first published online: 22 FEB 2006
- Received 22 May 2003; accepted 3 August 2003
- life cycle;
- mating system;
- pennate diatoms;
- sexual reproduction
The auxosporulation of Licmophora communis is allogamous and dioecious. Pairing between sessile, shortstalked cells of compatible clones is followed by meiosis and gametogenesis, to form two gametes in each gametangium. The behavior of the gametes differs between the gametangia. In the male gametangium, the gametes detach from the frustule, round up, and migrate out of the gametangium after its dehiscence at the broader, unattached pole. In the female gametangium, both gametes remain attached to the adjacent theca over almost their whole length and do not move. Plasmogamy therefore occurs within the female gametangium and this is where the zygotes are formed and remain. After fertilization, the zygotes detach from the thecae of the female gametangia, contract, and become ellipsoidal, before expanding parallel to the apical axis of the gametangium. We review the types of auxosporulation in other pennate diatoms and the systems used for classifying these. Dioecy and cis-type anisogamy (in which one gametangium produces active gametes and the other produces passive gametes), as in L. communis, are probably primitive within the pennate group (although there is no information on the AsterionellopsisRhaphoneis clade). However, size can also be restored in various araphid pennates by allogamous sexual reproduction involving the formation of only one gamete per gametangium, or in rare cases by automixis or (apparently) vegetative enlargement.