Sunflower seedlings (Helianthus annuus) shake it up in this streaming video
"Some of the most spectacular plant movements are nastic movements," says Plants-in-Motion, an Indiana University Biology Department website with streaming videos that reveal the secret movements of plants, normally too slow for the human eye to detect:
Nastic movements are plant movements that occur in response to environmental stimuli, but unlike tropic movements, the direction of the response is not dependent on the direction of the stimulus . . . These include the closing of the carnivorous Venus Flytrap leaf when it captures prey or the folding of the mimosa leaf when it is disturbed . . .
Cultivated sunflower plants grow best under full sunlight. Under the low light levels used when making this movie, it is easy to imagine that the seedlings are struggling to find more light. However, the cause of the nutational* movements is poorly understood.
*Nutation: A more or less rhythmical change in the position of growing plant organs due to variation in growth rates on different sides of the growing apex : an autonomic movement.
[via A Girl Named Zinc]
David Attenborough did the definitive work in this field in the mid-nineties, his magnificent The Private Life of Plants book and videos.