Cyanide helps plant regrowth

Cyanide helps plant regrowth

THE UNIVERSITY OF WESTERN AUSTRALIA

The Red and Green Kangaroo Paw is Western Australia's floral emblem. Image: SmileyJoanne/iStockphoto In work that could aid regeneration of bushfire-affected landscapes, it has been found that the germination of seeds of the red and green kangaroo paw - Western Australia's floral emblem - are greatly stimulated by the poison cyanide. ARC Postdoctoral Fellow Dr Gavin Flematti and colleagues of The University of Western Australia's School of Biomedical, Biomolecular and Chemical Sciences, along with collaborators from Kings Park and Botanic Garden and Murdoch University, have discovered that cyanide plays a crucial role in promoting the germination of dormant seeds in soil following a bushfire. In work published today in Nature Communications, Dr Flematti and colleagues report for the first time an ecological role for cyanide in seed germination. "We found when plants burn, they produce a substance that, after rain, hydrolyses to release cyanide.  We realised that cyanide is an important cue in landscape regeneration after fires, in a diverse range of fire-responsive plant species from different continents," Dr Flematti said. "Cyanide is well known for its toxicity towards many organisms, and it's known that many plants use it as a defence against herbivores but, until now, we hadn't understood its role in plant growth and ecosystem regeneration. "Many terrestrial ecosystems are subject to cycles of fire and regeneration, suggesting that this role of cyanide must have helped to shape the evolution of land plants, landscapes and whole ecosystems." Dr Flematti, along with Professor Emilio Ghisalberti, had also discovered the role of karrikins, a class of compounds in bushfire smoke that also promote germination.  However, the kangaroo paw is a species that does not respond to karrikins. "We now find that many plant species respond to both karrikins and cyanide, while some respond to only one, such as the kangaroo paw," Dr Flematti said.