Mother knows best—even if Mom is a plant. A common flowering plant, Arabidopsis, hands down “memories” of recent temperatures to its seeds to prepare them for incoming spring weather conditions, a new study shows.
In an experiment by crop geneticists in Norwich, England, Arabidopsis individuals exposed to warmer temperatures produced seeds that sprouted more quickly than plants exposed to cooler temperatures—even if the warmer temperatures had occurred several weeks before the parents made the seeds. The investigators, based at the independent plant research institution John Innes Center, the University of York and the University of Exeter, traced the difference to a protein involved in flowering. In cool weather, the protein levels prompt the mother plant to produce more tannin in its fruit. Tannin is a compound that makes seed casings strong, so higher levels make those shells harder for seedlings to break through, delaying germination. “The mother defines how hard the seed coat is to break free from, and in this way it's controlling what the seed does,” says Steven Penfield, a geneticist at John Innes and a co-author of the study, published in the Proceedings of the National Academy of Sciences USA. In warmer weather, the parent plant tweaks protein levels to make sure its offspring sprout immediately to take advantage of the heat.
Penfield notes that the finding has attracted interest from scientists and agricultural companies alike. As climate change shifts the timing of germination for many botanical species, his team's work suggests that modifying the genes involved in sensing the seasons could change when seeds sprout regardless of the weather outside.
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Coaxing plants to relinquish control of their seeds' sprouting times may be a crucial step toward making sure food grows consistently, says Kent Bradford, an agricultural researcher at the University of California, Davis, who is eager to see if lettuces have a similar process for regulating germination. “We're trying to adapt those populations to the environment we expect to be here 10, 20 years down the road.”