Thermoregulation in plants

Several primitive plants can generate enough heat to increase their floral temperature above ambient temperature by increasing their respiration. For instance, Symplocarpus renifolius and Arum maculatum are known to produce significant heat during the course of their floral development. In the case of S. renifolius, organ-specific thermogenesis occurs in the spadix, and it maintains a temperature of approximately 23oC even when ambient temperatures drop below freezing. In contrast, A. maculatum are known to raise their temperatures of appendices transiently at around 30oC. Our previous data showed that respiratory control in homeothermic spadices of S. renifolius is achieved by rate-determining biochemical reactions in which the overall thermodynamic activation energy exhibits a negative value. In the present study, we hypothesized that comparative de novo transcriptome analyses of thermogenic S. renifolius and A. maculatum provide an opportunity to discover genes involved in thermoregulation in plants.