Sexual dimorphism in the genus Leucadendron : Morphology and plant hydraulics

 

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dc.contributor.advisor West, Adam G en_ZA
dc.contributor.author van Blerk, Justin en_ZA
dc.date.accessioned 2015-09-15T10:32:50Z
dc.date.available 2015-09-15T10:32:50Z
dc.date.issued 2013 en_ZA
dc.identifier.citation van Blerk, J. 2013. Sexual dimorphism in the genus Leucadendron : Morphology and plant hydraulics. University of Cape Town. en_ZA
dc.identifier.uri http://hdl.handle.net/11427/14014
dc.description.abstract 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. en_ZA
dc.language.iso eng en_ZA
dc.subject.other Biological Sciences en_ZA
dc.title Sexual dimorphism in the genus Leucadendron : Morphology and plant hydraulics en_ZA
dc.type Bachelor Thesis
uct.type.publication Research en_ZA
uct.type.resource Thesis en_ZA
dc.publisher.institution University of Cape Town
dc.publisher.faculty Faculty of Science en_ZA
dc.publisher.department Department of Biological Sciences en_ZA
dc.type.qualificationlevel Honours
dc.type.qualificationname BSc (Hons) en_ZA
uct.type.filetype Text
uct.type.filetype Image
dc.identifier.apacitation van 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/11427/14014 en_ZA
dc.identifier.chicagocitation van 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/11427/14014 en_ZA
dc.identifier.vancouvercitation van 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/11427/14014 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


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