Macquarie University
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Functional analysis of extrafloral nectaries and nectar of Australian native wild cottons

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posted on 2022-03-28, 13:10 authored by Belinda K. Fabian
Extrafloral (EF) nectar is the foundation of many ant-plant interactions worldwide. EF nectar is a resource that encourages ant presence, in turn resulting in protection for plants against herbivores. There is a paucity of research on this relationship and the plant structures that underpin it in Australian species. An examination of the morphology and anatomy of EF nectaries of four Australian cottons (Gossypium spp.) revealed a suberised layer in the nectaries which indicates solutes must travel through the symplasm. ¹⁴CO₂ labelling showed the studied leaves were carbon sources and the EF nectar carbon cost was 1% of net photosynthates. Any environmental changes that affect EF nectar could have flow-on effects for ecological communities, for example rising atmospheric carbon dioxide (CO₂) levels. This study tested the response of EF nectar to elevated CO₂; the first investigation of elevated CO₂ impacts on any EF nectar system. The total volume and composition of EF nectar did not change, but there was evidence of accelerated plant development and a change in EF nectar allocation within plants. Developmental changes due to elevated CO₂ could affect the timing of EF nectar production which could have flow-on effects to ant mutualists and the defence of plants.


Table of Contents

Chapter 1. Extrafloral nectary anatomy and carbon metabolism of Australian native wild cottons (Gossypium spp.; Malvaceae) -- Chapter 2. Response of Australian native wild cotton (Gossypium spp.; Malvaceae) extrafloral nectar production and composition to elevate4d carbon dioxide.


Bibliography: pages 63-71 Thesis by publication.

Awarding Institution

Macquarie University

Degree Type

Thesis MRes


MRes, Macquarie University, Faculty of Science and Engineering, Department of Biological Sciences

Department, Centre or School

Department of Biological Sciences

Year of Award


Principal Supervisor

Brian Atwell

Additional Supervisor 1

Lesley Ann Hughes


Copyright Belinda K. Fabian 2015. Copyright disclaimer:






1 online resource (85 pages) colour illustrations

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