Scientists have discovered why the first buds of spring come increasingly earlier as the climate changes.

Researchers at the John Innes Centre have found that plants have an ideal temperature for seed set and flower at a particular time of year to make sure their seed develops just as the weather has warmed to this 'sweet spot' temperature.

"We found that setting seed at the correct temperature is vital to ensure normal germination," researcher Dr. Steven Penfield said in a statement.

Penfield and his colleague, Vicki Springthorpe found the sweet spot for the model plant Arabidposis thaliana is between 14-15 C. Seeds that develop in temperatures lower than 14 C will almost always remain dormant and fail to germinate. This allows the mother plant to produce seeds with different growth strategies, increasing the chances that some of her progeny will successfully complete another generation.

As the climate changes the sweet spot for seeds comes earlier in the year, so first flowers bloom correspondingly earlier too.

For the study, they used computer models to understand the growth strategy of Arabidopsis thaliana. The underlying principle of a very sensitive temperature sweet spot is likely to apply to many flowering plants. This would mean that certain plants have different flowering times due to different but equally narrow temperature sensitivity windows.

The findings are detailed in eLife.