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Photochemistry, energy dissipation and cold-hardening in Eucalyptus nitens and E. pauciflora


Hovenden, MJ and Warren, CR, Photochemistry, energy dissipation and cold-hardening in Eucalyptus nitens and E. pauciflora, Australian Journal of Plant Physiology, 25, (5) pp. 581-589. ISSN 0310-7841 (1998) [Refereed Article]

DOI: doi:10.1071/PP98027


The allocation of absorbed photon energy to thermal energy dissipation and photosynthetic electron transport was investigated as a function of photosynthetic photon flux density (PPFD) and temperature in two species of subalpine eucalypt, Eucalyptus nitens (Deane et Maiden) Maiden and E. pauciflora Sieb. ex Spreng. The proportion of absorbed light utilised in photosynthetic electron transport decreased with increasing PPFD, and the decrease was more pronounced the lower the temperature. The proportion diverted into dissipation processes increased with increasing PPFD to a maximum where it reached a plateau. This maximum increased with decreasing temperature. Exposure to a succession of cold (4°C) nights increased the photochemical quantum yield of photosystem II and decreased the allocation of excitation energy to thermal dissipation processes in conditions of excess light, particularly at low temperatures. Consequently, the photosynthetic electron transport rate (ETR) was higher and heat dissipation rate (HDR) was lower in hardened plants than in non-hardened plants at low temperatures. At 20°C, ETR was generally higher than HDR in all plants, but as the temperature decreased, HDR became the dominant process. The PPFD at which HDR exceeded ETR decreased with decreasing temperature, and at low temperatures was always lower in non-hardened plants than hardened plants, although quite similar between species.

Item Details

Item Type:Refereed Article
Research Division:Biological Sciences
Research Group:Plant biology
Research Field:Plant physiology
Objective Division:Expanding Knowledge
Objective Group:Expanding knowledge
Objective Field:Expanding knowledge in the environmental sciences
UTAS Author:Hovenden, MJ (Professor Mark Hovenden)
UTAS Author:Warren, CR (Mr Charles Robert Warren)
ID Code:15025
Year Published:1998
Web of Science® Times Cited:18
Deposited By:Plant Science
Deposited On:1998-08-01
Last Modified:2011-08-09

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