Hornwort Stomata: Architecture and Fate Shared with 400-Million-Year-Old Fossil Plants without Leaves
| Autor: | Amelia Merced, Jessica Regan Lucas, Bryan T. Piatkowski, Juan Carlos Villarreal, Karen S. Renzaglia |
|---|---|
| Rok vydání: | 2017 |
| Předmět: |
0106 biological sciences
0301 basic medicine Physiology Research Articles - Focus Issue Substomatal cavity Anthocerotophyta Plant Science Biology 01 natural sciences Cell wall Hornwort 03 medical and health sciences stomatognathic system Genome Size Microscopy Electron Transmission Cell Wall Plant Cells Guard cell Botany Genetics Fossils Sporangium fungi food and beverages Plant physiology Sporophyte biology.organism_classification Spore 030104 developmental biology Plant Stomata Pectins Genome Plant 010606 plant biology & botany |
| Zdroj: | Plant Physiology. 174:788-797 |
| ISSN: | 1532-2548 0032-0889 |
| DOI: | 10.1104/pp.17.00156 |
| Popis: | As one of the earliest plant groups to evolve stomata, hornworts are key to understanding the origin and function of stomata. Hornwort stomata are large and scattered on sporangia that grow from their bases and release spores at their tips. We present data from development and immunocytochemistry that identify a role for hornwort stomata that is correlated with sporangial and spore maturation. We measured guard cells across the genera with stomata to assess developmental changes in size and to analyze any correlation with genome size. Stomata form at the base of the sporophyte in the green region, where they develop differential wall thickenings, form a pore, and die. Guard cells collapse inwardly, increase in surface area, and remain perched over a substomatal cavity and network of intercellular spaces that is initially fluid filled. Following pore formation, the sporophyte dries from the outside inwardly and continues to do so after guard cells die and collapse. Spore tetrads develop in spore mother cell walls within a mucilaginous matrix, both of which progressively dry before sporophyte dehiscence. A lack of correlation between guard cell size and DNA content, lack of arabinans in cell walls, and perpetually open pores are consistent with the inactivity of hornwort stomata. Stomata are expendable in hornworts, as they have been lost twice in derived taxa. Guard cells and epidermal cells of hornworts show striking similarities with the earliest plant fossils. Our findings identify an architecture and fate of stomata in hornworts that is ancient and common to plants without sporophytic leaves. |
| Databáze: | OpenAIRE |
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