Sexual dimorphism in the genus Leucadendron : Morphology and plant hydraulics

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dc.contributor.advisorWest, Adam Gen_ZA
dc.contributor.authorvan Blerk, Justinen_ZA
dc.date.accessioned2015-09-15T10:32:50Z
dc.date.available2015-09-15T10:32:50Z
dc.date.issued2013en_ZA
dc.description.abstractThe genus, Leucadendron, of the Cape Proteaceae family, is made up of over 70 dioecious species that vary in their degree of sexual dimorphism. Males are generally more highly ramified (branched) with smaller leaves compared to corresponding females. It has been hypothesised that sexual dimorphism in Leucadendrons is linked to serotiny (a fire-adapted reproductive strategy), where highly serotinous females may incur extra resource costs in order to keep their transpiring cones alive between fires. This hypothesis predicts that the female morphology might be associated with more efficient resource acquisition compared to males in order to support their greater resource requirements. Another hypothesis suggests that selection for greater floral display in males has lead to a higher degree of ramification as male cones are borne terminally on branches. This highly branched morphology may be associated with subsequent physiological costs. The idea that different male and female morphologies might be associated with different physiological costs or benefits was tested in this experiment with a focus on plant hydraulics. Hydraulic supply is known to affect photosynthetic capacity and maximum assimilation rate. Using a specially designed vacuum chamber, leaf-specific and xylem-specific hydraulic conductance was measured in males and females of the highly dimorphic Leucadendron rubrum and non/marginally dimorphic Leucadendron daphnoides. Using microscopic imagery, xylem anatomy was analysed in an attempt to explain the hydraulic conductance results.en_ZA
dc.identifier.apacitationvan Blerk, J. (2013). <i>Sexual dimorphism in the genus Leucadendron : Morphology and plant hydraulics</i>. (Thesis). University of Cape Town ,Faculty of Science ,Department of Biological Sciences. Retrieved from http://hdl.handle.net/11427/14014en_ZA
dc.identifier.chicagocitationvan Blerk, Justin. <i>"Sexual dimorphism in the genus Leucadendron : Morphology and plant hydraulics."</i> Thesis., University of Cape Town ,Faculty of Science ,Department of Biological Sciences, 2013. http://hdl.handle.net/11427/14014en_ZA
dc.identifier.citationvan Blerk, J. 2013. Sexual dimorphism in the genus Leucadendron : Morphology and plant hydraulics. University of Cape Town.en_ZA
dc.identifier.ris TY - Thesis / Dissertation AU - van Blerk, Justin AB - The genus, Leucadendron, of the Cape Proteaceae family, is made up of over 70 dioecious species that vary in their degree of sexual dimorphism. Males are generally more highly ramified (branched) with smaller leaves compared to corresponding females. It has been hypothesised that sexual dimorphism in Leucadendrons is linked to serotiny (a fire-adapted reproductive strategy), where highly serotinous females may incur extra resource costs in order to keep their transpiring cones alive between fires. This hypothesis predicts that the female morphology might be associated with more efficient resource acquisition compared to males in order to support their greater resource requirements. Another hypothesis suggests that selection for greater floral display in males has lead to a higher degree of ramification as male cones are borne terminally on branches. This highly branched morphology may be associated with subsequent physiological costs. The idea that different male and female morphologies might be associated with different physiological costs or benefits was tested in this experiment with a focus on plant hydraulics. Hydraulic supply is known to affect photosynthetic capacity and maximum assimilation rate. Using a specially designed vacuum chamber, leaf-specific and xylem-specific hydraulic conductance was measured in males and females of the highly dimorphic Leucadendron rubrum and non/marginally dimorphic Leucadendron daphnoides. Using microscopic imagery, xylem anatomy was analysed in an attempt to explain the hydraulic conductance results. DA - 2013 DB - OpenUCT DP - University of Cape Town LK - https://open.uct.ac.za PB - University of Cape Town PY - 2013 T1 - Sexual dimorphism in the genus Leucadendron : Morphology and plant hydraulics TI - Sexual dimorphism in the genus Leucadendron : Morphology and plant hydraulics UR - http://hdl.handle.net/11427/14014 ER - en_ZA
dc.identifier.urihttp://hdl.handle.net/11427/14014
dc.identifier.vancouvercitationvan Blerk J. Sexual dimorphism in the genus Leucadendron : Morphology and plant hydraulics. [Thesis]. University of Cape Town ,Faculty of Science ,Department of Biological Sciences, 2013 [cited yyyy month dd]. Available from: http://hdl.handle.net/11427/14014en_ZA
dc.language.isoengen_ZA
dc.publisher.departmentDepartment of Biological Sciencesen_ZA
dc.publisher.facultyFaculty of Scienceen_ZA
dc.publisher.institutionUniversity of Cape Town
dc.subject.otherBiological Sciencesen_ZA
dc.titleSexual dimorphism in the genus Leucadendron : Morphology and plant hydraulicsen_ZA
dc.typeBachelor Thesis
dc.type.qualificationlevelHonours
dc.type.qualificationnameBSc (Hons)en_ZA
uct.type.filetypeText
uct.type.filetypeImage
uct.type.publicationResearchen_ZA
uct.type.resourceThesisen_ZA
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