2 September 2004

Exotic flowers that can raise their temperature by as much as 35 degrees Celsius above surrounding air temperature and generate heat for insects as a reward for pollination is the focus of a free seminar being held at Charles Darwin University tomorrow.

Roger in Philodendron

Professor Roger Seymour is visiting Charles Darwin University from the University of Adelaide and will present the seminar being hosted by the Faculty of Education, Health and Science.

Professor Seymour is an animal physiologist but he has recently turned his attention to some of the most unusual plants in the world which includes the sacred lotus flower found in the Territory.

"The flowers of many primitive seed plants produce metabolic heat during blooming, some even raising floral temperature as much as 35C above air temperature, with respiratory rates equivalent to those of active birds and mammals," Professor Seymour explained.

"Several are known to regulate floral temperature by increasing heat production when ambient temperature decreases.

Humans and other mammals and birds regulate their body temperatures with a thermostat in their brains, but plants lack brains and must regulate their heat production actually in the cells that produce it.

“Exactly how they do this is unknown, but it is currently being investigated at Adelaide and with a colleague in Japan.”

Professor Seymour also indicated that some work is being done to reveal the mystery as to why the flowers regulate their temperature.

“Recent measurements regarding pollination of philodendrons by scarab beetles in the South American nation of French Guiana demonstrates that the flower's ability to raise its temperature actually represents an energy reward for the beetle's floral visitation.

"This is the first demonstration of a plants 'reward' for insect generated pollination other than food such as nectar or pollen.

“One of the best temperature-regulating flowers is the sacred lotus, common in the rivers and billabongs of the Northern Territory. The sacred lotus can remain at 32C, even if air temperature is experimentally decreased to 7C or raised to 46C. It regulates its temperature better than many mammals.”