Seed Dormancy: a 360 Million-Year-Old Mystery
The phenomenon of seed dormancy - when seeds wait for the right conditions to germinate for months, if not years at a time - has always fascinated experts. Now, researchers have discovered that seeds lay dormant even 360 million years ago, adding a bit more mystique to the already mysterious property.
A new study published in the journal New Phytologist describes how researchers Carol and Jerry Baskin led an international effort to analyze features of seed dormancy in more than 14,000 species of plants. The pair has been studying the phenomenon of seed latency - how a seed delays its germination - since the early 1960s, and even so, they still remain unsure of how this stunning adaptation evolved.
What the analysis did find was that seed dormancy is as old as the seeds themselves, in that even the eldest of seed specimens from the dawn of terrestrial plant life already boasted "very sophisticated adjustments to environmental conditions."
Interestingly, the analysis also revealed that plants without the ability to delay their germination tended to be less capable of diversification, where non-dormant plants have significantly smaller trees of evolution and adaptation.
"This can be due to the fact that dormancy facilitates that germination only takes place at the optimal moment, in spite of changes in the environment, due either to weather phenomena, or whether due to the fact that the seeds reach a new location after dispersal," Rafael Rubio de Casas, a researcher from the University of Granada, explained in a statement. "This adjustment of the plant cycle to the new environment can reduce the probability of a particular species to become extinct."
Amazingly, despite being a very old adaptation, dormancy does not seem simple. According to the study, many of the original mechanisms of dormancy (which can vary) cannot even be tricked.
"Seeds do not germinate even when conditions are [temporarily] favorable, which precludes germination after a summer storm, or during a few warm days in winter," de Casas added.
This seeming "plant intelligence" is similar to how many resilient tree species won't be tricked by a tricky climate, despite what appears to be ideal conditions to turn out their leaves.
However, the researchers are quick to point out that dormancy is not always preferable. In the case of domesticated crops, for instance, the property was one of the first traits to go as farmers learned when and how to sow seeds for maximum yield.