A unified approach was used to analyse the energy budgets and temperatures of flowers belonging to the families Rafflesiaceae and Convolvulacea; and some broader ecological and evolutionary implications of their thermal regimes were discussed. Rhizanthes lowii and Raflessia tuan-mudae (Rafflesiaceae) are rare parasitic plants adapted to live in the understory of the tropical rain forest in South East Asia. In the understory of the forest the ambient conditions are nearly constant (high relative humidity, low incident radiation and relatively constant air and soil temperature). These plants are parasitic on the vine Tretrastigma. They lack leaves, stems, or photosynthetic tissue and are characterised by gaseous emissions that attract the natural pollinators, carrion flies. The internal and surface temperatures of the flowers were continuously monitored with fine thermocouples in different parts of the flowers whilst radiation fluxes and microclimatic variables were recorded. In the case of Rhizanthes lowii there was evidence of both thermogenesis and thermoregulation. Endothermy was detected in young and mature buds as well as in blooming flowers and even in decaying tissues three or more days after blooming. Tissue temperatures were maintained at 7 - 9 K above air temperature. In Rafflesia tuan-mudae it was found that the internal parts of the flower were maintained a few degrees (1-6 K) above air temperature and the maximum heating was in the evening. As they are parasitic, they have the advantage over most other species as the respiratory substrate is derived from the host plant. High concentrations of CO2 may be released as the product of respiration. A fluid dynamics model was used to estimate the CO2 concentration in the reproductive cavity of Rafflesia tuan-mudae. The model suggested that the flower developed high concentrations of carbon dioxide inside the diaphragm, mainly around the central column where the cavity with the reproductive parts (anther or stigma) are located.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:660419 |
| Date | January 2001 |
| Creators | Patino, Sandra |
| Publisher | University of Edinburgh |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://hdl.handle.net/1842/11877 |
Page generated in 0.0021 seconds