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Respiration of thermogenic inflorescences of skunk cabbage Symplocarpus renifolius in heliox
Author(s) -
Seymour Roger S.,
Ito Kikukatsu,
Umekawa Yui
Publication year - 2018
Publication title -
plant, cell and environment
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.646
H-Index - 200
eISSN - 1365-3040
pISSN - 0140-7791
DOI - 10.1111/pce.13097
Subject(s) - heliox , respiration , inflorescence , biology , chemistry , botany , physiology
The respiration rate of the thermogenic inflorescences of Japanese skunk cabbage Symplocarpus renifolius can reach 300 nmol s −1 g −1 , which is sufficient to raise spadix temperature (T s ) up to 15 ° C above ambient air temperature (T a ). Respiration rate is inversely related to T a , such that the T s achieves a degree of independence from T a , an effect known as temperature regulation. Here, we measure oxygen consumption rate (Ṁ o 2 ) in air (21% O 2 in mainly N 2 ) and in heliox (21% O 2 in He) to investigate the diffusive conductance of the network of gas‐filled spaces and the thermoregulatory response. When T s was clamped at 15 ° C, the temperature that produces maximal Ṁ o 2 in this species, exposure to high diffusivity heliox increased mean Ṁ o 2 significantly from 137 ± 17 to 202 ± 43 nmol s −1 g −1 FW, indicating that respiration in air is normally limited by diffusion in the gas phase and some mitochondria are unsaturated. When T a was clamped at 15 ° C and T s was allowed to vary, exposure to heliox reduced T s 1 ° C and increased Ṁ o 2 significantly from 116 ± 10 to 137 ± 19 nmol s −1 g −1 , indicating that enhanced heat loss by conduction and convection can elicit the thermoregulatory response.