Please use this identifier to cite or link to this item: https://hdl.handle.net/2440/61998
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Type: Journal article
Title: Respiration and temperature patterns in thermogenic flowers of Magnolia ovata under natural conditions in Brazil
Author: Seymour, R.
Silberbauer-Gottsberger, I.
Gottsberger, G.
Citation: Functional Plant Biology: an international journal of plant function, 2010; 37(9):870-878
Publisher: C S I R O Publishing
Issue Date: 2010
ISSN: 1445-4408
Statement of
Responsibility: 
Roger S. Seymour, Ilse Silberbauer-Gottsberger and Gerhard Gottsberger
Abstract: The roles of floral thermogenesis in pollination biology include attraction and reward of insects. Magnolia ovata (A.St.-Hil.) Spreng. produces ~56 g, bisexual, protogynous and scented flowers. Two distinct episodes of thermogenesis occur during anthesis: one beginning at about sunset and lasting ~3 h in the female phase and another that occurs synchronously 24 h later and lasting 4 h in the male phase. Female stage flowers produce up to 0.36 W to reach 27.3°C, which is 3.9°C above ambient air. In the male stage, corresponding values are 0.79 W, 29.7°C and 5.4°C, respectively. Most heat is generated in the petals in both phases (74 and 65%). Maximum, mass-specific rate of respiration is 23 nmol s–1 g–1 in the petals and 100 nmol s–1 g–1 in the anthers. The flowers are apparently not thermoregulatory, because respiration rate decreases, rather than increases, with decreasing ambient temperature. Scarab beetles, Cyclocephala literata, enter the floral chamber created by the petals in the female phase, mate, consume floral parts (mainly petals) and then depart in the male phase. Temperatures maintained in the floral chamber are sufficient to provide beetles with significant energy savings during their activities in both phases. Thermogenesis is, therefore, consistent with volatilisation of floral fragrances and energy rewards to beetle visitors.
Keywords: Calorimetry
heat production
Magnoliaceae
respiratory rate
Rights: © CSIRO 2010
DOI: 10.1071/FP10039
Grant ID: ARC
Appears in Collections:Aurora harvest
Earth and Environmental Sciences publications

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