I read an article in Scientific American (50 years ago, before they forgot the definition of science), that plants turn toward the sun because the stems produce more chloroform on their sunny side, causing the stem to twist.
Just another one of those amazing things that evolve from chaos. ;)
I was in a family store, all alone, no business.
I hear rustling, like paper falling on other paper.
Turn around, the plant is shaking. No air conditioning running - it was inside a mall, away from mall entrances.
However, the glass of the store faced East, and the mall glass was across the walkway about another 10 feet out.
One day, for fun, I took a magic marker and made very small mark across the center stem and branches so I could mark the growth and the rotation.
At night I’d turn the plant away from the Sun - but it would turn towards the lights on at night in the store.
After the Sun was up the next day, they’d rotate towards the Sun.
It was pretty cool to observe that first time.