We are using a systems biology approach to elucidate the mechanisms by which the flowers of certain plants, such as the sacred lotus ( Nelumbo nucifera ) and Philodendron selloum are able to maintain above-ambient stable temperatures without the complex homeostatic processes present in animals. This international collaboration involves researchers in four countries Dr Jennifer Watling (University of Adelaide, Australia), Dr Rebecca Miller (Monash University, Australia ) Dr. Kikukatsu Ito , (Iwate University, Japan), Larry Giles and Dr Joe Berry (Carnegie Institution for Science Department of Global Ecology, USA) and Miquel Ribas-Carbo (Universitat de les Illes Ballears, Spain )
The energy for heating these floral ovens comes from uncoupled respiration in the plant mitochondria. Stable isotopes are used to show which respiratory pathways are active in these plants (Ribas_Carbo et al 2005) and we have shown that the sacred lotus uses the alternative oxidase to produce all its heat (Watling et al 2006 & 2008; Grant et al 2008). In Philodendron the situation seems to be more complex and this plant may use both the alternative oxidase and uncoupling proteins to turbo charge its flowers to 42 °C. We are using a combination of proteomic and biochemical techniques as well as on-line gas chromatography mass spectrometry techniques to investigate how heating is regulated. Recent highlights include the first measurements of in vivo fluxes through the alternative pathway in thermogenic tissues (Watling et al , 2006 PDF 260k).
Grant NM, Miller RE, Watling JR, Robinson SA (2008) Synchronicity of thermogenic activity, alternative pathway respiratory flux, AOX protein content and carbohydrates in receptacle tissues of sacred lotus during floral development. Journal of Experimental Botany 59 705-714.
Watling, J.R., Robinson, S.A. Seymour, R.S (2006) Contribution of the alternative pathway to respiration during thermogenesis in flowers of the sacred lotus. Plant Physiology 140, 1367-1373
 Watling et al, 2006 (PDF 260k) |
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Lambers, H., Robinson, S.A., Ribas-Carbo, M. (2005) Regulation of respiration in vivo. In Plant Respiration: from cell to ecosystem, Advances in Photosynthesis and Respiration v18 (H. Lambers. M Ribas-Carbo eds.). Springer, Dordrecht, The Netherlands, pp 1-15.
Ribas-Carbo, M., Robinson, S.A., Giles, L. (2005) The application of oxygen isotope technique to respiratory pathway partitioning. In Plant Respiration: from cell to ecosystem, Advances in Photosynthesis and Respiration v18 (H. Lambers. M Ribas-Carbo eds.). Springer, Dordrecht, The Netherlands, pp 31-42.
Robinson, S.A., Ribas-Carbo, M., Yakir, D., Giles, L. and Berry, J.A. (1995). Beyond SHAM and cyanide: opportunities for studying the alternative oxidase in plant respiration using oxygen isotope discrimination. Aust. J. Plant Physiol. 22 487-96.
Ribas-Carbo, M., Robinson, S.A., Gonzàlez-Meler, M.A Lennon, A.M., Giles, L., Siedow, J.N. and Berry, J.A. (2000) Effects of light on respiration and oxygen isotope fractionation in soybean cotyledons. Plant Cell and Environment 23 983-989.
Paper in PDF (192k)
