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The autecology of Stipa Trichotoma Nees (Nassella Tussock) on Rhodes Estate, in the South-Western Cape
[Page 1 missing] The autecology of Stipa trichotoma Nees (nassella tussock) was studied in the Mediterranean-type climate of the south-western Cape. The study site was Rhodes Estate, on the lower slopes of Devil •s Peak. The relative growth rate of tussocks in the field was studied using nondestruct...
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| Language: | English |
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Department of Biological Sciences
2024
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| _version_ | 1867613231605874688 |
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| access_status_str | Open Access |
| author | Harding, Graham Bruce |
| author_browse | Harding, Graham Bruce |
| author_facet | Harding, Graham Bruce |
| author_sort | Harding, Graham Bruce |
| collection | Thesis |
| description | [Page 1 missing] The autecology of Stipa trichotoma Nees (nassella tussock) was studied in the Mediterranean-type climate of the south-western Cape. The study site was Rhodes Estate, on the lower slopes of Devil •s Peak. The relative growth rate of tussocks in the field was studied using nondestructive methods while more accurate biomass experiments were undertaken on nursery grown plants. These experiments revealed that nassella tussock has a relatively low growth rate with maximum growth occurring in spring to early summer. The phenology was studied for two seasons. The times and duration of flowering were noted as well as the numbers of inflorescences and fruits produced. The stages of flowering were also noted. Floral initiation occurred in early summer with fruits being dispersed in January to February. Variation in fruit shape and colour was found. Cleistogamy was found to be common and to result in relatively short fat fruits. Cleistogamy occurred in shaded tussocks or inflorescences. The germination of nassella tussock was also studied. The pattern of germination was found to be variable which suggested that the evolution of localized ecotypes could have occurred. Dormancy was found to be limited and to occur after fruit dispersal: The degree of dormancy varied between the experimental sites. Germination could be enhanced by leaching fruits in running water for a few days. This and a simple bioassay suggested the presence of an inhibitor or complex of inhibitors, probably located in the lemma and palea. Reports that burning I enhanced the germination of nassella tussock could not be repeated by simulation in the laboratory. -Nassella tussock was found to have a limited distribution. This was thought to be controlled mainly by the state of the vegetation. Nassella tussock is, however, adapted to the climate of the south~western Cape. |
| format | Thesis |
| id | oai:open.uct.ac.za:11427/40483 |
| institution | University of Cape Town (South Africa) |
| language | eng |
| last_indexed | 2026-06-10T12:32:51.499Z |
| license_str | Not specified — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UCTD — University of Cape Town Open Access Repository |
| publishDate | 2024 |
| publishDateRange | 2024 |
| publishDateSort | 2024 |
| publisher | Department of Biological Sciences |
| publisherStr | Department of Biological Sciences |
| record_format | dspace |
| source_str | UCTD — University of Cape Town Open Access Repository |
| spelling | oai:open.uct.ac.za:11427/40483 The autecology of Stipa Trichotoma Nees (Nassella Tussock) on Rhodes Estate, in the South-Western Cape Harding, Graham Bruce Botony [Page 1 missing] The autecology of Stipa trichotoma Nees (nassella tussock) was studied in the Mediterranean-type climate of the south-western Cape. The study site was Rhodes Estate, on the lower slopes of Devil •s Peak. The relative growth rate of tussocks in the field was studied using nondestructive methods while more accurate biomass experiments were undertaken on nursery grown plants. These experiments revealed that nassella tussock has a relatively low growth rate with maximum growth occurring in spring to early summer. The phenology was studied for two seasons. The times and duration of flowering were noted as well as the numbers of inflorescences and fruits produced. The stages of flowering were also noted. Floral initiation occurred in early summer with fruits being dispersed in January to February. Variation in fruit shape and colour was found. Cleistogamy was found to be common and to result in relatively short fat fruits. Cleistogamy occurred in shaded tussocks or inflorescences. The germination of nassella tussock was also studied. The pattern of germination was found to be variable which suggested that the evolution of localized ecotypes could have occurred. Dormancy was found to be limited and to occur after fruit dispersal: The degree of dormancy varied between the experimental sites. Germination could be enhanced by leaching fruits in running water for a few days. This and a simple bioassay suggested the presence of an inhibitor or complex of inhibitors, probably located in the lemma and palea. Reports that burning I enhanced the germination of nassella tussock could not be repeated by simulation in the laboratory. -Nassella tussock was found to have a limited distribution. This was thought to be controlled mainly by the state of the vegetation. Nassella tussock is, however, adapted to the climate of the south~western Cape. 2024-07-23T13:17:23Z 2024-07-23T13:17:23Z 1982 2024-07-23T07:00:10Z Thesis / Dissertation Masters MSc http://hdl.handle.net/11427/40483 eng application/pdf Department of Biological Sciences Faculty of Science |
| spellingShingle | Botony Harding, Graham Bruce The autecology of Stipa Trichotoma Nees (Nassella Tussock) on Rhodes Estate, in the South-Western Cape |
| thesis_degree_str | Master's |
| title | The autecology of Stipa Trichotoma Nees (Nassella Tussock) on Rhodes Estate, in the South-Western Cape |
| title_full | The autecology of Stipa Trichotoma Nees (Nassella Tussock) on Rhodes Estate, in the South-Western Cape |
| title_fullStr | The autecology of Stipa Trichotoma Nees (Nassella Tussock) on Rhodes Estate, in the South-Western Cape |
| title_full_unstemmed | The autecology of Stipa Trichotoma Nees (Nassella Tussock) on Rhodes Estate, in the South-Western Cape |
| title_short | The autecology of Stipa Trichotoma Nees (Nassella Tussock) on Rhodes Estate, in the South-Western Cape |
| title_sort | autecology of stipa trichotoma nees nassella tussock on rhodes estate in the south western cape |
| topic | Botony |
| url | http://hdl.handle.net/11427/40483 |
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