How sunflowers track the sun's movements

The process of plants tracking the course of the sun is known as heliotropism and can be observed most famously in the sunflower. Dr Mike Haydon, University of Melbourne, explains this magnificent feat of flora.

[cmills]

Where I live, they do not. The summers sun is too hot for their little faces in summer, and they carefully turn their faces away from the sun all day. (GA USA)

[justindecker]

We are going to have to remake this video now that they are turning there back on the sun

[felixromano]

In Spanish sunflowers are called girasoles or “sun spinners” 😮 I did not know why until today

[j.anthony]

Why have sunflowers been turning away from the sun?

[supremebeme]

i heard there is a strange phenomena where they are no longer tracking the sun this year

[sactownsluckylady]

Today is July 26, 2024 and sunflowers are turning their backs or faces from whatever the sun is now!

[HansDunkelberg]

"Circadian clock" is just a word. It explains nothing.

[marcmelancon]

When is someone going show the time lapse. I know I have seen the video.

[ReformedAgnostic]

That's an interesting explanation of *why* they do it, but the question of *how* they do it - without muscles - wasn't even addressed. I know it seems like an elementary, and therefore silly, question, but precisely how does a sunflower turn? What goes on in the stem to make them turn? *EDIT:* Turns out that, during the day, the east-facing part of the sunflower stem grows more than the west-facing side, which turns the sunflower from east to west - tracking the sun. At night, the reverse happens; the west-facing part of the stem grows more than the east-facing part, which causes the sunflower to turn east to await the rising of the sun.

[tinaalmeidam]

Mine stopped.2 years ago and the last year I planted them they were all deformed, but this was after we had fall out from Palestine train wreck in Ohio.

[injusticeanywherethreatens]

They didnt actually answer how tho so....

[NQBN]

In persian we literally call then sun worshippers

[lookingcloud]

Use peashooters just incase zombies or cattapilars😅💛🌻

[Kormac]

Nature spirits co-evolved with all and they guide such activities based on the needs of the plants, animals, insects, earth, water, etc