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Switching off the heater: influence of ambient temperature on thermoregulation by eastern skunk cabbage Symplocarpus foetidus

Switching off the heater: influence of ambient temperature on thermoregulation by eastern skunk... Abstract The protogynous inflorescences of eastern skunk cabbage, Symplocarpus foetidus, are thermogenic and regulate spadix temperature (Ts) well above ambient temperature (Ta). Continuous records of oxygen consumption, carbon dioxide production, and temperatures of plants were made at a field site in Canada. At Ta between 3–24 °C, Ts ranged between 16–26 °C, and the warmest inflorescences were those in the receptive female or early pollen-bearing stages. Respiratory rates of the 2-g spadices increased with declining Ta, and reached a maximum of 0.54 µmol O2 s−1 (0.73 ml min−1), equivalent to 0.26 W of heat production. At Ta below 3 °C, several inflorescences failed to maintain high Ts and abruptly switched Ts to near freezing. Some froze when Ta dropped to about −10 °C. Those that did not freeze could quickly switch to the warm state if Ta rose above about 3 °C. Switching was related to the balance between heat production and heat loss that tended to produce stable equilibria at either high or low Ts. Switching between warm and cool states resulted in a bimodal distribution of Ts in the field. A respiratory quotient of 1.0 showed that carbohydrate was the substrate for thermogenesis, and bomb calorimetry of florets confirmed that energy was imported from the root. Only 11 invertebrates, including only one flying insect, were found in 195 inflorescences, suggesting that heat production and temperature regulation are not closely associated with cross-pollination. Oxygen consumption, heat production, thermogenesis, temperature regulation, Araceae This content is only available as a PDF. © Oxford University Press 1999 © Oxford University Press 1999 http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Journal of Experimental Botany Oxford University Press

Switching off the heater: influence of ambient temperature on thermoregulation by eastern skunk cabbage Symplocarpus foetidus

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References (18)

Publisher
Oxford University Press
Copyright
Copyright © 2022 Society for Experimental Biology
ISSN
0022-0957
eISSN
1460-2431
DOI
10.1093/jxb/50.338.1525
Publisher site
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Abstract

Abstract The protogynous inflorescences of eastern skunk cabbage, Symplocarpus foetidus, are thermogenic and regulate spadix temperature (Ts) well above ambient temperature (Ta). Continuous records of oxygen consumption, carbon dioxide production, and temperatures of plants were made at a field site in Canada. At Ta between 3–24 °C, Ts ranged between 16–26 °C, and the warmest inflorescences were those in the receptive female or early pollen-bearing stages. Respiratory rates of the 2-g spadices increased with declining Ta, and reached a maximum of 0.54 µmol O2 s−1 (0.73 ml min−1), equivalent to 0.26 W of heat production. At Ta below 3 °C, several inflorescences failed to maintain high Ts and abruptly switched Ts to near freezing. Some froze when Ta dropped to about −10 °C. Those that did not freeze could quickly switch to the warm state if Ta rose above about 3 °C. Switching was related to the balance between heat production and heat loss that tended to produce stable equilibria at either high or low Ts. Switching between warm and cool states resulted in a bimodal distribution of Ts in the field. A respiratory quotient of 1.0 showed that carbohydrate was the substrate for thermogenesis, and bomb calorimetry of florets confirmed that energy was imported from the root. Only 11 invertebrates, including only one flying insect, were found in 195 inflorescences, suggesting that heat production and temperature regulation are not closely associated with cross-pollination. Oxygen consumption, heat production, thermogenesis, temperature regulation, Araceae This content is only available as a PDF. © Oxford University Press 1999 © Oxford University Press 1999

Journal

Journal of Experimental Botany – Oxford University Press

Published: Sep 1, 1999

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