Scientists have known for years that some seeds after being dormant in the soil for years can be triggered to germinate and sprout after a wildland fire. But exactly how this happened was not clear.
Recent research by personnel at the Salk Institute for Biological Studies has shed some light on this process. Below are some excerpts from an article at Science Daily:
[Joseph P.] Noel’s co-senior investigator on the project, Joanne Chory, professor and director of Salk’s Plant Molecular and Cellular Biology Laboratory, says the team found the molecular “wake-up call” for burned forests. “What we discovered,” she says, “is how a dying plant generates a chemical message for the next generation, telling dormant seeds it’s time to sprout.”
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In previous studies, scientists had discovered that special chemicals known as karrikins are created as trees and shrubs burn during a forest fire and remain in the soil after the fire, ensuring the forest will regenerate.
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The chemical structures the team solved revealed all the molecular contacts between karrikin and KAI2, according to Salk research associate Yongxia Guo, a structural enzymologist and one of the study’s lead investigators. “But, more than that,” Gou says, “we also now know that when karrikin binds to the KAI2 protein it causes a change in its shape.”
The studies’ other lead investigator, Salk research associate and plant geneticist Zuyu Zheng, says this karrikin-induced shape change may send a new signal to other proteins in the seeds. “These other protein players,” he says, “together with karrikin and KAI2, generate the signal causing seed germination at the right place and time after a wildfire.”
