Fig. 1

Intermediate petal determines flower opening and closure movement rhythm. a Floral opening and closure rhythm in Nymphaea nouchali cut flowers was tracked from 7:00 to 23:00. b Floral opening-closure rhythm without sepal. c Without sepal, the floral opening and closure rhythm was tracked when only 1 cm of the petal was left. White arrows highlighted the movement rhythm of the petals. d Without the sepal and stamen, the floral opening and closure rhythm was tracked when only 1 cm of the petal was left. White arrows highlighted the movement rhythm of the petals. e-f Floral opening-closure angles were measured according to the above pictures. Blue rectangular boxes below the curves highlight the maximum opening period. Scale bar, 25 mm (a-d). Error bar = SEM (e, f)