Meet the Karrikins, a newly discovered family of chemicals found in the smoke and haze leftover after fires decimate forests and grasslands.

Karrikins, unlike the destructive combustion that creates them, are nurturers. They spur plant seeds to germinate and signal plant seedlings to adopt a stumpier shape that protects them from exposed conditions, according to new research from University of Western Australia and Kings Park and Botanic Garden.

“These molecules show us that one of the ways that fire operates in the world’s ecosystems is by changing the light sensitivity of seeds via signaling chemicals that come from the fire itself,” said Prof. Kingsley Dixon of Kings Park in Perth, Australia.

Karrikins are formed from burning cellulose, the molecule that makes up the cell walls in plants.

The molecules are only one out of 4,000 chemicals found to be made when plant material burns.

Although wildfire ecologists had long observed patterns of extreme plant growth after wildfires, until now, they had not discovered which of those 4,000 chemical products might be causing the flora’s rebirth.

After a fire, the Karrikin molecules in the smoke enter the seeds. Sending signals to the plant’s genetic molecules, Karrikins make the botanicals extra sensitive to sunlight so that plants emerge with less exposure.

The molecules also turn on genes preventing the plant from getting too tall or thin, so they’ll have a better chance of survival in exposed, post-fire conditions.

“The Karrikins precondition the plant so that it doesn’t get leggy and long and so won’t be damaged by too much sunshine or wind exposure, or other threats,” said Dixon.

Karrikin-exposed Arabadopsis Thalinia plants, which Dixon called the ‘lab rats’ of the plant world, ended up 25 to 30 percent shorter than their peers and their first leaves were 50 percent fatter according to the study, published in the Proceedings of the National Academy of Sciences.

Researchers named the chemicals after “karrik” which means smoke in the language of the Noongar people, native inhabitants of Western Australia. “We did this research on Noongar land and wanted to celebrate their culture,” Dixon said.

The Karrikins were found in extremely low concentrations and produced profound effects even in plants that don’t grow in areas of fire threat, Dixon said.

This led the research team to think they might have found a powerful plant hormone that could be used for communication within the plant as well as for communication between the plant and its environment.

“This may in fact be an internal regulatory chemical that has eluded people before,” Dixon said.

There is still more to learn about Karrikins and their internal workings, but we’ve a huge leap just by identifying them.  Understanding Karrikins can only help us better understand the impact that fires have on the land and how they affect the natural cycle of plants.