Spores before sporophytes : hypothesizing the origin of sporogenesis at the algal-plant transition
© 2011 The Authors. New Phytologist © 2011 New Phytologist Trust.
| Veröffentlicht in: | The New phytologist. - 1979. - 190(2011), 4 vom: 01. Juni, Seite 875-881 |
|---|---|
| 1. Verfasser: | |
| Weitere Verfasser: | |
| Format: | Online-Aufsatz |
| Sprache: | English |
| Veröffentlicht: |
2011
|
| Zugriff auf das übergeordnete Werk: | The New phytologist |
| Schlagworte: | Journal Article Biopolymers sporopollenin 12712-72-0 Carotenoids 36-88-4 |
| Zusammenfassung: | © 2011 The Authors. New Phytologist © 2011 New Phytologist Trust. Fossil spores from mid-Ordovician deposits (475 million yr old) are the first indication of plants on land and predate megafossils of plants by 30-50 million yr. Sporopollenin-walled spores distinguish land plants from algae, which typically have heavy-walled zygotes that germinate via meiosis into motile or protonemal cells. All land plants are embryophytes with spores produced by the sporophyte generation. It is generally assumed that retention of the zygote and delay in meiosis led to matrotrophic embryo development and intercalation of the diploid sporophyte before spore production. However, new data on the cell biology of sporogenesis in extant bryophytes suggest that spores were produced directly from zygotes in protoembryophytes. The mechanism of wall transfer from zygote to meiospores was a three-phase heterochrony involving precocious initiation of cytokinesis, acceleration of meiosis, and concomitant delay in wall deposition. In bryophyte sporogenesis, cytokinesis is typically initiated in advance of meiosis, and quadrilobing of the cytoplasm is followed by development of a bizarre quadripolar spindle that assures coordination of nuclear distribution with predetermined spore domains. This concept of the innovation of sporogenesis at the onset of terrestrialization provides a new perspective for interpreting fossil evidence and understanding the evolution of land plants |
|---|---|
| Beschreibung: | Date Completed 25.08.2011 Date Revised 09.04.2022 published: Print-Electronic Citation Status MEDLINE |
| ISSN: | 1469-8137 |
| DOI: | 10.1111/j.1469-8137.2011.03709.x |