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Water relations, carbon fixation and growth rates of two leaf succulent species under different water regimes
The leaf succulent species R.carolii and R.multiflora are common in the winter rainfall Karoo. Despite their similar growth form, their distribution in Worcester Veld Reserve appeared to differ. R.multiflora occupied a more exposed, arid North - facing slope, while R.carolii dominated a protected So...
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| Format: | Thesis |
| Language: | English |
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Department of Biological Sciences
2023
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| _version_ | 1867613208547688448 |
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| access_status_str | Open Access |
| author | Beukman, Ruth Pam |
| author2 | Stock, W D |
| author_browse | Beukman, Ruth Pam Stock, W D |
| author_facet | Stock, W D Beukman, Ruth Pam |
| author_sort | Beukman, Ruth Pam |
| collection | Thesis |
| description | The leaf succulent species R.carolii and R.multiflora are common in the winter rainfall Karoo. Despite their similar growth form, their distribution in Worcester Veld Reserve appeared to differ. R.multiflora occupied a more exposed, arid North - facing slope, while R.carolii dominated a protected South facing slope. Possible reasons for this distribution were investigated. Plants of the two species were established in a growth chamber and subjected to different water regimes. The diurnal patterns of water loss and ca1rbon gain were investigated under optimal and drought conditions after 30, 50 and 60 days of treatment. Gas exchange data of both species showed that C3 photosynthesis was adopted when ·the plants - were irrigated regularly, but also tended to accumulate malate, which indicated the activity of RuBPc and PEPc. R.carolii had higher photosynthetic and growth rates than R.multiflora under optimal conditions. This explained the dominance of R.carolii on the South facing, protected slope. Under moderate water stress, the species behaved similarly. There was a tendency towards CAM activity, though results were inconclusive. During periods of extreme water shortage. R.carolii exhibited limited stomatal response and thus appeared to be dying, while R.multiflora adopted day time stomatal opening a and CO2 uptake. This strategy and in general the high tolerance to water stress shown by R.multiflora allowed it to outcompete R.carolii on the arid, exposed, North facing slope. |
| format | Thesis |
| id | oai:open.uct.ac.za:11427/38946 |
| institution | University of Cape Town (South Africa) |
| language | eng |
| last_indexed | 2026-06-10T12:32:29.432Z |
| 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 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:11427/38946 Water relations, carbon fixation and growth rates of two leaf succulent species under different water regimes Beukman, Ruth Pam Stock, W D Midgley, G Botany The leaf succulent species R.carolii and R.multiflora are common in the winter rainfall Karoo. Despite their similar growth form, their distribution in Worcester Veld Reserve appeared to differ. R.multiflora occupied a more exposed, arid North - facing slope, while R.carolii dominated a protected South facing slope. Possible reasons for this distribution were investigated. Plants of the two species were established in a growth chamber and subjected to different water regimes. The diurnal patterns of water loss and ca1rbon gain were investigated under optimal and drought conditions after 30, 50 and 60 days of treatment. Gas exchange data of both species showed that C3 photosynthesis was adopted when ·the plants - were irrigated regularly, but also tended to accumulate malate, which indicated the activity of RuBPc and PEPc. R.carolii had higher photosynthetic and growth rates than R.multiflora under optimal conditions. This explained the dominance of R.carolii on the South facing, protected slope. Under moderate water stress, the species behaved similarly. There was a tendency towards CAM activity, though results were inconclusive. During periods of extreme water shortage. R.carolii exhibited limited stomatal response and thus appeared to be dying, while R.multiflora adopted day time stomatal opening a and CO2 uptake. This strategy and in general the high tolerance to water stress shown by R.multiflora allowed it to outcompete R.carolii on the arid, exposed, North facing slope. 2023-09-29T07:17:04Z 2023-09-29T07:17:04Z 1988 2023-09-29T07:14:34Z Bachelor Thesis Honours Honours http://hdl.handle.net/11427/38946 eng application/pdf Department of Biological Sciences Faculty of Science |
| spellingShingle | Botany Beukman, Ruth Pam Water relations, carbon fixation and growth rates of two leaf succulent species under different water regimes |
| thesis_degree_str | Bachelor's / Honours |
| title | Water relations, carbon fixation and growth rates of two leaf succulent species under different water regimes |
| title_full | Water relations, carbon fixation and growth rates of two leaf succulent species under different water regimes |
| title_fullStr | Water relations, carbon fixation and growth rates of two leaf succulent species under different water regimes |
| title_full_unstemmed | Water relations, carbon fixation and growth rates of two leaf succulent species under different water regimes |
| title_short | Water relations, carbon fixation and growth rates of two leaf succulent species under different water regimes |
| title_sort | water relations carbon fixation and growth rates of two leaf succulent species under different water regimes |
| topic | Botany |
| url | http://hdl.handle.net/11427/38946 |
| work_keys_str_mv | AT beukmanruthpam waterrelationscarbonfixationandgrowthratesoftwoleafsucculentspeciesunderdifferentwaterregimes |