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Dry and back again: characterization of desiccation-associated differentiation of leaf tissues in Craterostigma pumilum Hochst
Resurrection plants are a polyphyletic group of angiosperms which display true desiccation tolerance - the ability to survive near complete loss of cellular water for extended periods, while recovering metabolic competence upon watering. This is achieved by employing tailored protection behaviours d...
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| Format: | Thesis |
| Language: | English |
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Department of Molecular and Cell Biology
2023
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| _version_ | 1867613245548789760 |
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| access_status_str | Open Access |
| author | Du Toit, Stephanus Francois |
| author2 | Farrant, Jill Margaret |
| author_browse | Du Toit, Stephanus Francois Farrant, Jill Margaret |
| author_facet | Farrant, Jill Margaret Du Toit, Stephanus Francois |
| author_sort | Du Toit, Stephanus Francois |
| collection | Thesis |
| description | Resurrection plants are a polyphyletic group of angiosperms which display true desiccation tolerance - the ability to survive near complete loss of cellular water for extended periods, while recovering metabolic competence upon watering. This is achieved by employing tailored protection behaviours depending on the relative state of (de)hydration. Recent work has raised interest in desiccation associated changes related to tissue destiny in desiccation tolerant vegetative tissues. In this thesis, physiological and transcriptomic techniques were used to characterize such a phenomenon in the homoiochlorophyllous dicot resurrection plant Craterostigma pumilum. Detailed phenotypic observation and pulse-amplitude-modulation fluorometry were used to identify the critical water contents at which key physiological changes occur in leaves of C. pumilum and how this relates to desiccation-associated differentiation between leaf Tip and Base tissues. This was followed by transcriptomic analyses and comparison between these two tissues, to identify potentially key processes involved in desiccation associated tissue differentiation. All findings were then synthesised with existing information reported on for other resurrection plant species to create a theoretical model of desiccation-associated tissue differentiation. This differentiation phenomenon is shown to be transcriptionally initiated during the desiccation commitment stage of the C. pumilum dehydration cycle but is only realised phenotypically during early rehydration and after initial water movement through the leaf tissues. This work provides strong evidence for the existence of desiccation-associated tissue differentiation in C. pumilum and highlights the potential involvement of the phytohormone auxin in the determination of leaf tissue responses to progressive dehydration and anhydrobiosis in resurrection plants. |
| format | Thesis |
| id | oai:open.uct.ac.za:11427/38471 |
| institution | University of Cape Town (South Africa) |
| language | eng |
| last_indexed | 2026-06-10T12:33:05.164Z |
| license_str | Not specified — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UCTD — University of Cape Town Open Access Repository |
| publishDate | 2023 |
| publishDateRange | 2023 |
| publishDateSort | 2023 |
| publisher | Department of Molecular and Cell Biology |
| publisherStr | Department of Molecular and Cell Biology |
| record_format | dspace |
| source_str | UCTD — University of Cape Town Open Access Repository |
| spelling | oai:open.uct.ac.za:11427/38471 Dry and back again: characterization of desiccation-associated differentiation of leaf tissues in Craterostigma pumilum Hochst Du Toit, Stephanus Francois Farrant, Jill Margaret Reich, Ziv Leaf Tissues Craterostigma pumilum Hochst Resurrection plants are a polyphyletic group of angiosperms which display true desiccation tolerance - the ability to survive near complete loss of cellular water for extended periods, while recovering metabolic competence upon watering. This is achieved by employing tailored protection behaviours depending on the relative state of (de)hydration. Recent work has raised interest in desiccation associated changes related to tissue destiny in desiccation tolerant vegetative tissues. In this thesis, physiological and transcriptomic techniques were used to characterize such a phenomenon in the homoiochlorophyllous dicot resurrection plant Craterostigma pumilum. Detailed phenotypic observation and pulse-amplitude-modulation fluorometry were used to identify the critical water contents at which key physiological changes occur in leaves of C. pumilum and how this relates to desiccation-associated differentiation between leaf Tip and Base tissues. This was followed by transcriptomic analyses and comparison between these two tissues, to identify potentially key processes involved in desiccation associated tissue differentiation. All findings were then synthesised with existing information reported on for other resurrection plant species to create a theoretical model of desiccation-associated tissue differentiation. This differentiation phenomenon is shown to be transcriptionally initiated during the desiccation commitment stage of the C. pumilum dehydration cycle but is only realised phenotypically during early rehydration and after initial water movement through the leaf tissues. This work provides strong evidence for the existence of desiccation-associated tissue differentiation in C. pumilum and highlights the potential involvement of the phytohormone auxin in the determination of leaf tissue responses to progressive dehydration and anhydrobiosis in resurrection plants. 2023-09-08T11:52:08Z 2023-09-08T11:52:08Z 2023 2023-09-08T11:44:39Z Doctoral Thesis Doctoral PhD http://hdl.handle.net/11427/38471 eng application/pdf Department of Molecular and Cell Biology Faculty of Science |
| spellingShingle | Leaf Tissues Craterostigma pumilum Hochst Du Toit, Stephanus Francois Dry and back again: characterization of desiccation-associated differentiation of leaf tissues in Craterostigma pumilum Hochst |
| thesis_degree_str | Doctoral |
| title | Dry and back again: characterization of desiccation-associated differentiation of leaf tissues in Craterostigma pumilum Hochst |
| title_full | Dry and back again: characterization of desiccation-associated differentiation of leaf tissues in Craterostigma pumilum Hochst |
| title_fullStr | Dry and back again: characterization of desiccation-associated differentiation of leaf tissues in Craterostigma pumilum Hochst |
| title_full_unstemmed | Dry and back again: characterization of desiccation-associated differentiation of leaf tissues in Craterostigma pumilum Hochst |
| title_short | Dry and back again: characterization of desiccation-associated differentiation of leaf tissues in Craterostigma pumilum Hochst |
| title_sort | dry and back again characterization of desiccation associated differentiation of leaf tissues in craterostigma pumilum hochst |
| topic | Leaf Tissues Craterostigma pumilum Hochst |
| url | http://hdl.handle.net/11427/38471 |
| work_keys_str_mv | AT dutoitstephanusfrancois dryandbackagaincharacterizationofdesiccationassociateddifferentiationofleaftissuesincraterostigmapumilumhochst |