The Sound of Science - "Blooming Flowers"

Apr 26, 2019

K: I’m Kate Powers from NIU STEM Outreach with Jeremy Benson and this is the Sound of Science on WNIJ.

J: Kate, I have a question from Jeannine today. She wants to know how plants know when to bloom.

K: That’s a great question, especially considering how wacky our winter was this year. If plants bloom too soon and then a late cold snap happens, they risk frost damage. 

NIU STEM Outreach

J: Right. How do plants know not to bloom during a warm spell in the middle of January?

K: This is a question that has intrigued scientists for centuries and inspired awe in humans since the beginning of time! We even have a name for the study of periodic plant and animal life cycles called phenology, which started as the study of when plants begin to bloom.

J: Phenology? Isn’t that the pseudoscience of predicting people’s characteristics by studying the shape of their skull?!

K: No, that’s phrenology! Phenology is a very valid science. But they do sound the same. Observationally we know that flowers pop up in the spring when the weather warms. But not all plants bud and flower at the same time. 

J: Right, we see the crocuses and tulips first, then other flowers follow and some even bloom as late as the fall.

K: Exactly. Scientists have determined that plants use a protein called Flowering Locus T. This is the protein that plants send to their shoot apex. Once there the Flowering Locus T can trigger the molecular change that will eventually create flowers.

J: That’s interesting, but how do plants know the right time to bloom?

K: Plants have a circadian clock just like humans do. Plants lay in wait during the winter, measuring the amount of light available each day. When enough sunlight is present they will begin their growth. Different plants bloom at different times because they have different needs.

J: Oh, like maybe they have a relationship with a pollinator that comes out at a specific time in the season?

K: Exactly. They may also need warmer temperatures and a lot of water, or they might be hardy and bloom at an unusual time to avoid competition from other plants. Crocuses don’t need to worry about other plants blocking their sunlight - When they start poking their little buds out of the snow, no other plants are around yet!

J: Well I’m glad to see all the green that’s showing up now. It’s been a long winter and I’m glad the plants know just the right time to bloom. Keep those questions coming to stemoutreach@niu.edu. This has been the Sound of Science on WNIJ.

K: Where you learn something new every day.